Found two pretty serious bugs:
Battles against the Golem Reign don't end, even when all enemies have been defeated. I also noticed that there's always one enemy that leaves an invisible but impassable object upon death. I'm guessing that one of the Reign Battle-only golem types isn't correctly removed from the map upon death (thus making the game think that there are still enemies present). This bug applies to both field battles and siege battles.
The other bug has already been reported before, but I'm still running into it even with 0.16.11 patch 2;
Script 'Sapphire Action System IV' line 338: RGSSError occured.
disposed bitmap
If you start the game, enter a combat map, and you (or an enemy) use a projectile weapon (like Wind Blade, etc.), everything will work normally. But if you leave that map, enter a different combat map, and then use a projectile weapon again, you'll get this error and the game will close itself. The same will happen if you go back to title, load a game, and then use a projectile weapon.