An engine needs to transit a switch but is halted. There is an active train already claiming that switch, so the engine waits. The claiming engine couples to its target consist and exits the area, releasing the switch (green arrow for waiting engine). However, the engine held, awaiting the switch, never moves. It forgets what it is waiting for. Ran the session two more times and the release of the switch worked and the waiting engine completed its tasks. Will run a few more times to make sure it was a "one-time".