I'm getting these 3 error messages repeating almost every minute in my server. I recently moved my websites from 2008R2 to 2016 and since then I have a few sites that are giving me these errors.

I've posted about this on stack-overflow initially but have not got any feedback other than it's Lucene related which is on the error logs.

Application: w3wp.exe
Framework Version: v4.0.30319 Description: The process was terminated due to an unhandled exception. Exception Info: System.IndexOutOfRangeException    at Lucene.Net.Index.IndexWriter.HandleMergeException(System.Exception, OneMerge)    at Lucene.Net.Index.IndexWriter.Merge(OneMerge)    at Lucene.Net.Index.ConcurrentMergeScheduler+MergeThread.Run()Exception Info: Lucene.Net.Index.MergePolicy+MergeException    at Lucene.Net.Index.ConcurrentMergeScheduler.HandleMergeException(System.Exception)    at Lucene.Net.Index.ConcurrentMergeScheduler+MergeThread.Run()    at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)    at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)    at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)    at System.Threading.ThreadHelper.ThreadStart()

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Faulting application name: w3wp.exe, version: 10.0.14393.0, time stamp: 0x57899b8a Faulting module name: KERNELBASE.dll, version: 10.0.14393.0, time stamp: 0x57899809 Exception code: 0xe0434352 Fault offset: 0x0000000000017788 Faulting process id: 0x1840 Faulting application start time: 0x01d27de3c8a59141 Faulting application path: c:\windows\system32\inetsrv\w3wp.exe
Faulting module path: C:\Windows\System32\KERNELBASE.dll
Report Id: b8c443b9-7658-47b3-ae17-40d304a55c82 Faulting package full name:Faulting package-relative application ID: 

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An unhandled exception occurred and the process was terminated.Application ID: /LM/W3SVC/25/ROOT
Process ID: 6208Exception: Lucene.Net.Index.MergePolicy+MergeExceptionMessage: Exception of type 'Lucene.Net.Index.MergePolicy+MergeException' was thrown.StackTrace:    at Lucene.Net.Index.ConcurrentMergeScheduler.HandleMergeException(Exception exc)    at Lucene.Net.Index.ConcurrentMergeScheduler.MergeThread.Run()    at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)    at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)    at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)    at System.Threading.ThreadHelper.ThreadStart()InnerException: System.IndexOutOfRangeExceptionMessage: Index was outside the bounds of the array.StackTrace:    at Lucene.Net.Index.IndexWriter.HandleMergeException(Exception t, OneMerge merge)    at Lucene.Net.Index.IndexWriter.Merge(OneMerge merge)    at Lucene.Net.Index.ConcurrentMergeScheduler.MergeThread.Run()