[dba-Tech] Weird Gmail error message

Every once in a while I get a strange message from Gmail that says
something like, "You have replied to an email in a trashed conversation.
Click here to move it to your Inbox." Sometimes this occurs when replying
to a message; other times it occurs when composing a new message (in which
case it truly makes no sense).

Anyone have a clue why this occurs?

Tia

-- 
Arthur