Zombie sessions (8.1.47)?

Ok one more question on the sessions topic.. Is it possible (or normal) for “zombie” sessions to get stuck on the server? I get this error (and I do know why this error happened) but the strange thing is that the “line 4 in openWatchList” it reports to be on has now moved (added checking and try blocks). Thoughts?

< This is a popup triggered on condition with a binding on the screen. >

Perspective on Ignition 8.1.47

Error running property change script on view.custom.showPopup: Traceback (most recent call last): File "function:valueChanged", line 10, in valueChanged File "", line 4, in openWatchList at com.inductiveautomation.perspective.gateway.script.AbstractScriptingFunctions.getSession(AbstractScriptingFunctions.java:111) at com.inductiveautomation.perspective.gateway.script.AbstractScriptingFunctions.operateOnSession(AbstractScriptingFunctions.java:118) at com.inductiveautomation.perspective.gateway.script.AbstractScriptingFunctions.operateOnPage(AbstractScriptingFunctions.java:47) at com.inductiveautomation.perspective.gateway.script.PerspectiveScriptingFunctions.popupAction(PerspectiveScriptingFunctions.java:758) at com.inductiveautomation.perspective.gateway.script.PerspectiveScriptingFunctions.openPopup(PerspectiveScriptingFunctions.java:240) at jdk.internal.reflect.GeneratedMethodAccessor131.invoke(Unknown Source) at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.base/java.lang.reflect.Method.invoke(Unknown Source) java.lang.IllegalStateException: java.lang.IllegalStateException: Session is not running.