[OJS 3.1.1-4 to 3.1.2-1] Discussion Sender displays as wrong username

We encountered a strange problem that we cannot replicate again under controlled circumstances. Hoping someone else has seen it, too!

When one of our editors sent out a Discussion, it was logged with both the Editor’s actual username & date (Nov 23), as well as the username of an unrelated Author’s username who should NOT have had access to the Submission at all, logged on a date about 1 month prior (Oct 27). Why would OJS log 2 senders for the same message?

For context: we upgraded from 3.1.1-4 to 3.1.2-1 on Nov 20. Thanks!