Ok, I can send you at least one example (from this morning) and will look for others.
But I still don't understand the problem in general. Isn't the auto-sig treated as a separate entity within groups.io that's added to the message content by the system?
BTW, in the message I'm going to send, the person's email auto-sig ("Get Outlook for Android") was included and not their (information-rich) groups.io sig with all their cat's info. Very discouraging!
Messages are the sole opinion of the author, especially the fishy ones.