It seems to be a driver corruption related to an asciinema-recorded
   tmux session I have open.
   I began a new recording of the same session, and the error changed to
   simply closing the connection.
   The error did not happen when unrecorded outside the session, or from
   other systems.
   The system has ram exhausted and has swap on an external drive, so
   maybe it's possible the swap is getting corrupt, not sure.