Since 10.7.6 when using an env_var for report.rules as such:

report.rules=file:///${env_var\:PARASOFT_DIR}/rules/docs/

The plugin crashes:

11:20:25 [Parasoft Findings] Searching for all files in 'C:\Jenkins\workspace\workspace\some_app' that match the pattern 'parasoft_reports/report.xml'
11:20:25 [Parasoft Findings] Traversing of symbolic links: enabled
11:20:25 [Parasoft Findings] -> found 1 file
11:20:25 [Parasoft Findings] Successfully parsed file C:\Jenkins\workspace\workspace\some_app\report.xml
11:20:25 [Parasoft Findings] -> found 5 issues (skipped 0 duplicates)
11:20:25 [Parasoft Findings] Successfully processed file 'parasoft_reports\report.xml'
Found unhandled hudson.remoting.ProxyException exception:
java.nio.file.InvalidPathException: Illegal char <:> at index 10: \${env_var:PARASOFT_DIR}\rules\docs
java.base/sun.nio.fs.WindowsPathParser.normalize(WindowsPathParser.java:182)
java.base/sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:153)
java.base/sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:77)
java.base/sun.nio.fs.WindowsPath.parse(WindowsPath.java:92)
java.base/sun.nio.fs.WindowsFileSystem.getPath(WindowsFileSystem.java:232)
java.base/java.io.File.toPath(File.java:2387)
PluginClassLoader for parasoft-findings//com.parasoft.findings.utils.doc.RuleDocumentationLocationHelper.checkDocRootLocation(RuleDocumentationLocationHelper.java:136)
PluginClassLoader for parasoft-findings//com.parasoft.findings.utils.doc.RuleDocumentationLocationHelper.createCustomLocalLoc(RuleDocumentationLocationHelper.java:111)
PluginClassLoader for parasoft-findings//com.parasoft.findings.utils.doc.RuleDocumentationLocationHelper.createCustomLoc(RuleDocumentationLocationHelper.java:106)
PluginClassLoader for parasoft-findings//com.parasoft.findings.utils.doc.RuleDocumentationLocationHelper.getRuleDocLocation(RuleDocumentationLocationHelper.java:62)
PluginClassLoader for parasoft-findings//com.parasoft.findings.utils.doc.RuleDocumentationProvider.getRuleDocLocation(RuleDocumentationProvider.java:74)
PluginClassLoader for parasoft-findings//com.parasoft.findings.jenkins.internal.rules.RuleDocumentationStorage.storeRuleDoc(RuleDocumentationStorage.java:67)
PluginClassLoader for parasoft-findings//com.parasoft.findings.jenkins.tool.ParasoftTool.scan(ParasoftTool.java:110)
PluginClassLoader for warnings-ng//io.jenkins.plugins.analysis.core.steps.IssuesScanner.scan(IssuesScanner.java:113)
PluginClassLoader for warnings-ng//io.jenkins.plugins.analysis.core.steps.IssuesRecorder.scanWithTool(IssuesRecorder.java:763)
PluginClassLoader for warnings-ng//io.jenkins.plugins.analysis.core.steps.IssuesRecorder.record(IssuesRecorder.java:687)
PluginClassLoader for warnings-ng//io.jenkins.plugins.analysis.core.steps.IssuesRecorder.perform(IssuesRecorder.java:663)
PluginClassLoader for warnings-ng//io.jenkins.plugins.analysis.core.steps.RecordIssuesStep$Execution.run(RecordIssuesStep.java:671)
PluginClassLoader for warnings-ng//io.jenkins.plugins.analysis.core.steps.RecordIssuesStep$Execution.run(RecordIssuesStep.java:627)
PluginClassLoader for workflow-step-api//org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution.lambda$start$0(SynchronousNonBlockingStepExecution.java:49)
java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)