Just for the sake of chronicling what I’d guess is related database quirkiness, although not a disappearing post, I’ll report that yesterday Earthling started a thread in GQ to which I replied. The board hung on submit, so I closed that browser and opened another to come back to the forum. There were two copies of the thread there, both showing zero replies and both containing my reply.
After communication with an administrator, my money’s back on the hamsters. Una, thank you for sharing your hands-on experience with this exact issue, it’s much appreciated.