Strange behaviour with columns in a saved filter

Scott has an email subscription to the "Kudos Report - Kudos in last week" filter.

The filter should have the following columns: Nominee, Summary, Reporter, Type, Reason For Kudos

Recently there have been a few anomalies in the subscription emails that he gets:

• Emails began coming through with different columns to what were saved in the "filter" (Summary, Reporter, Created, Type)
• The columns then fixed themselves for one week after I looked at them (and found nothing wrong)
• The past two weeks they've changed again to a the same set of columns in the first dot point above (Summary, Reporter, Created, Type)
• Scott checked the filter to see what columns were saved, and it turned out that they'd been changed in the issue navigator - he had not touched them, and he's the owner of the filter.

I'm thinking that this erroneous case may be caused by the upgrades we do on EACJ. It'd be awesome if we could investigate to see if we can find a cause.

Feel free to ask me if you have any q's.