The indexer crashed on me. Granted, I had lots of apps open and probably memory usage was high, so not enough memory for indexing to complete. But a more graceful exit with a meaningful error message would be expected rather than a crash.
Log files:
1222.LogosIndexerCrash 2019-06-04.zip
Task Manager Memory Usage screenshot:

Resource Monitor screenshot. Note that Logos is the largest culprit in memory usage.
