There was indeed a known issue in a previous game version (GPU memory buffer issue) that caused crashes, most commonly during combat.
In the game update currently being prepared, there are changes to how textures are compressed which may help if your crashes are related to the previous problem, and IIRC another fix for a problem that could cause crashes (though quite rarely).
How often does it crash? If you reload a save near the end of the fight, is it likely to finish properly after you reload, or crash again?
Are the crashes that are not at the end of a fight still usually during combat?
Are you still in Fort Joy?
Did the crashing start from the beginning, or was it ok / less common earlier in the game, and then start / get worse with larger fights or after getting to the area after Fort Joy, etc?
Is there a pattern to when the crashes happen, besides the end of fights (when there are lost of opponents / surfaces / summons, if combat takes a long time, etc)?
Try clearing the system cache: in the Home menu open System Settings, then select System, Formatting Options, Clear Cache and then the current user.
Note that this will also reset the system language and brightness setting.