Steps to reproduce:

1) Create a new Freestyle project.  (I used the name testbuild)

2) Go down to the Post build step and add IRC Notification

3) Specify channel.

4) Click on Apply,

The following error appears in the log:

2021-01-07 07:32:44.688+0000 [id=156] WARNING h.i.i.InstallUncaughtExceptionHandler#handleException: Caught unhandled exception with ID ac09e597-52ed-493e-8f2c-d61f72922b9e
java.lang.NoSuchFieldError: PARAMETERVALUE_STRATEGY_VALUES
at hudson.plugins.ircbot.IrcPublisher$DescriptorImpl.newInstance(IrcPublisher.java:407)
at hudson.plugins.ircbot.IrcPublisher$DescriptorImpl.newInstance(IrcPublisher.java:140)
at hudson.model.Descriptor.newInstancesFromHeteroList(Descriptor.java:1075)
at hudson.model.Descriptor.newInstancesFromHeteroList(Descriptor.java:1037)
at hudson.util.DescribableList.rebuildHetero(DescribableList.java:208)
at hudson.model.Project.submit(Project.java:231)
at hudson.model.Job.doConfigSubmit(Job.java:1335)
at hudson.model.AbstractProject.doConfigSubmit(AbstractProject.java:770)
at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627)
at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:396)
at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:408)
at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:212)
at org.kohsuke.stapler.SelectionInterceptedFunction$Adapter.invoke(SelectionInterceptedFunction.java:36)
at org.kohsuke.stapler.verb.HttpVerbInterceptor.invoke(HttpVerbInterceptor.java:48)
at org.kohsuke.stapler.SelectionInterceptedFunction.bindAndInvoke(SelectionInterceptedFunction.java:26)
at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:145)
at org.kohsuke.stapler.MetaClass$11.doDispatch(MetaClass.java:536)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:766)
Caused: javax.servlet.ServletException
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:816)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:898)
at org.kohsuke.stapler.MetaClass$4.doDispatch(MetaClass.java:281)
at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:766)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:898)
at org.kohsuke.stapler.Stapler.invoke(Stapler.java:694)
at org.kohsuke.stapler.Stapler.service(Stapler.java:240)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:763)
at org.eclipse.jetty.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1633)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:154)
at jenkins.security.ResourceDomainFilter.doFilter(ResourceDomainFilter.java:76)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
at jenkins.telemetry.impl.UserLanguages$AcceptLanguageFilter.doFilter(UserLanguages.java:129)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
at com.cloudbees.jenkins.support.slowrequest.SlowRequestFilter.doFilter(SlowRequestFilter.java:37)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
at com.smartcodeltd.jenkinsci.plugin.assetbundler.filters.LessCSS.doFilter(LessCSS.java:47)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
at hudson.plugins.greenballs.GreenBallFilter.doFilter(GreenBallFilter.java:64)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
at jenkins.metrics.impl.MetricsFilter.doFilter(MetricsFilter.java:125)
at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:157)
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1609)
at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:153)
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1609)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at jenkins.security.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:119)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at jenkins.security.BasicHeaderProcessor.doFilter(BasicHeaderProcessor.java:93)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:67)
at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:90)
at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171)
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1609)
at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:51)
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1609)
at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82)
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1609)
at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30)
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1609)
at jenkins.security.SuspiciousRequestFilter.doFilter(SuspiciousRequestFilter.java:36)
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1609)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:561)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:578)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1612)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1434)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:501)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1582)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1349)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
at org.eclipse.jetty.server.Server.handle(Server.java:516)
at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:383)
at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:556)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:375)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:273)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)
at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:336)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:313)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:171)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:129)
at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:375)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:773)
at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:905)
at java.lang.Thread.run(Thread.java:748)

I tried this on two different instances on two different machines and I get the same error.