The Nodes monitoring didn't refresh for some time (showed N/A for values) and I found this in the logs:
```

2021-04-07 08:39:02.655+0000 [id=2406340] WARNING h.ExpressionFactory2$JexlExpression#evaluate: Caught exception evaluating: m.data(c) in /computer/. Reason: java.lang.IllegalStateException: WTF? Can't parse - as integer percentage2021-04-07 08:39:02.655+0000 [id=2406340] WARNING h.ExpressionFactory2$JexlExpression#evaluate: Caught exception evaluating: m.data(c) in /computer/. Reason: java.lang.IllegalStateException: WTF? Can't parse - as integer percentagejava.text.ParseException: - at org.jenkinsci.plugins.inodesnodemonitor.InodesMonitor.parse(InodesMonitor.java:59) at org.jenkinsci.plugins.inodesnodemonitor.InodesMonitor.data(InodesMonitor.java:71)Caused: java.lang.IllegalStateException: WTF? Can't parse - as integer percentage at org.jenkinsci.plugins.inodesnodemonitor.InodesMonitor.data(InodesMonitor.java:94) at sun.reflect.GeneratedMethodAccessor2914.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.commons.jexl.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:258) at org.apache.commons.jexl.parser.ASTMethod.execute(ASTMethod.java:104) at org.apache.commons.jexl.parser.ASTReference.execute(ASTReference.java:83) at org.apache.commons.jexl.parser.ASTReference.value(ASTReference.java:57) at org.apache.commons.jexl.parser.ASTReferenceExpression.value(ASTReferenceExpression.java:51) at org.apache.commons.jexl.ExpressionImpl.evaluate(ExpressionImpl.java:80) at hudson.ExpressionFactory2$JexlExpression.evaluate(ExpressionFactory2.java:74) at org.apache.commons.jelly.tags.core.CoreTagLibrary$3.run(CoreTagLibrary.java:134) at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95) at org.apache.commons.jelly.tags.core.CoreTagLibrary$1.run(CoreTagLibrary.java:98) at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:161) at org.apache.commons.jelly.tags.core.ForEachTag.doTag(ForEachTag.java:150) at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:269) at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95) at org.kohsuke.stapler.jelly.ReallyStaticTagLibrary$1.run(ReallyStaticTagLibrary.java:100) at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:161) at org.apache.commons.jelly.tags.core.ForEachTag.doTag(ForEachTag.java:150) at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:269)
```

I suspect that it happened because one node was offline