It is possible that I have stumbled across the source of the problem...maybe. When I retired from the FS, the email addy there obviously was discontinued. That was the addy I listed when I originally registered at the THouse. I had been meaning to update my profile with a current email address, and did so this morning...and so far, have not been auto-logged off.
I don't know enough to guess how this works, but you other few with this problem might check to see if your profile has a valid email addy listed.