This can be observed in the LiveRunningTest, that fails very often with

Caused by: org.apache.lucene.index.IndexNotFoundException: no segments* file found in InfinispanDirectory{indexName='emails'}: files: []
	at org.apache.lucene.index.SegmentInfos$FindSegmentsFile.run(SegmentInfos.java:726)
	at org.apache.lucene.index.SegmentInfos$FindSegmentsFile.run(SegmentInfos.java:683)

The cache entry that contains the list of files the lucene directory (FileListCacheValue) for some reason is empty, although the index is not. The missing value for FileListCacheValue causes the index reader to think the index is empty and thus the error