On Wed, Jan 23, 2019 at 10:28 AM, I wrote:
Let me double check things first!
...which I have now done, and my findings confirm my earlier comments. I reported my own message but neither the message itself nor the entire thread vanished as a result.
My comment about "Reply to Sender" was a red herring; that is the current default set by Shal for a different test a few days ago.
Referring the absence of anything in the Activity Log (confirmed!) is a good candidate for beta; can I suggest that you enlist the help of another of your group's members to try to replicate the test I did, just to be sure... there is no point in referring something that cannot be repeated.
Chris