Duplicate entries in History Log
History Log capturing snapshot of fields and records them in the History Log even when not modified. They appear as "Updated:" but display no red/blue before and after comparison. The User listed on the entry usually edited a different field but their name is posted to the extra snapshot as well.
version: 6.9 P2
Observed so far few Text Area fields are affected in one application and few values list fields in another application.
Those duplicates are pushing us to the default limit a lot faster. We make History Log entries every day, we are pushing entries off the visible cliff every day too (The number of history log entries exceeds maximum allowable for display).
You can make a History Log as a Link instead of Grid to show more entries, if you have not done already.
If you are sure the fields are not touched by user but still affected, you may want to contact Support for performing debug session in case you can reliably simulate the issue.