I've experienced a few ground combat bugs, mostly related to attacks on already defeated enemy forces (in these cases,
alien ruin robotic soldiers). Last time, the enemy unit was destroyed during its first attack, before my forces were even ordered to attack. I missed that and ordered the attack on the
Precursor forces. The force itself still existed, because there hadn't been a "general ground attack" event yet, so the next cycle I got a bunch of errors and a seemingly infinite succession of this one...
Error in GroundCombat
Error 3420 was generated by DAO.Recordset
The object is not valid or has no value. (translated from Spanish)
I had to kill Aurora's process after a while, since there was no apparent end to the identical pop-ups, even holding down Enter. When I restarted the game, I cancelled the attack, and the cycle processed just fine.