In version 1.4.12223.2017, I am getting the above message when I first go into VS 2017. It refers me to an activity log, where the relevant part seems to be:
<entry>
<record>802</record>
<time>2020/11/10 09:01:32.788</time>
<type>Error</type>
<source>Editor or Editor Extension</source>
<description>System.NullReferenceException: Object reference not set to an instance of an object.
 at Devsense.PHP.ControlFlow.Graph.BuilderVisitor..ctor(Statement[] statements)
 at PHP.VisualStudio.Language.Nodes.Project.ProjectAnalysis.AnalyseRoutine(IRoutine routine, CallInfo call, LocalsState callState)
 at PHP.VisualStudio.Language.Nodes.Project.ProjectAnalysis.EnsureRoutineAnalysed(IRoutine routine)
 at PHP.VisualStudio.Language.Nodes.Project.ProjectAnalysis.AnalyseNodeNoLock(GlobalCodeNode node)
 at PHP.VisualStudio.Language.Nodes.Project.ProjectAnalysis.AnalyseNode(GlobalCodeNode node)
 at 	
.InvokeTask()
 at PHP.VisualStudio.Language.TaskQueue.


	 .
()
--- End of stack trace from previous location where exception was thrown ---
 at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)</description>
</entry>
If I continue, everything seems to be OK, I hope......................................