Index rotation not deleting .old files

Hello,

The last couple of weeks we have been experiencing an issue where after plain index rotation the .old files are not removed on some random indexes.

For example, out of 10 indexes, 2 of them will not have their .old files removed:
manticore screenshot

Both the logging of searchd and the indexer don’t indicate any issues.

Is there any additional logging we can check to find what is causing this?

Yes. searchd --logdebug or set global log_level=debug