Any progress on the issue?
I assume this bug causes troubles for AIs.
B380586 8 on Nuclear_Winter_v1 - in the middle of the game (~40th minute unfortunatly) CircuitAI and then CAI tries to attack terraunit, that means terraunit got into LOS/Radar somehow. Strangly enough can't reproduce it: in quick-short experiments terraunit never generates EnemyEnterLOS or EnemyEnterRadar events.
Random thoughts:
Can it be due to messed unit id when id of dead unit reused?
Or something below water-height related?
Make terraunit destructable, or autodestruct on timeout?
Edit: On second thought it is probably not a big deal for AIs, should be solvable with proper onlyTargetCategory processing.