Re: Falling through the map.
Seems that using the melee attack, I find mostly with swords, this occurs in many places. The animation can end with you being outside of the map area or put you inside a crate/object, then you fall through the map.
Always seems to occur whilst "in combat" so maybe some lag issue with video drivers/data transfer whilst in such situations. But I've only ever fallen out of map during melee fights. Which usually kills Ryder and reloads a save from before the fight even started, which say versus an Archtect that's almost dead.. is kinda annoying. (melee killing a spawned bot)
On a few occasions I've killed a unit and fallen out of map during combat and just been teleported back to the surface, which seems to be the default "fix" for the problem.
