I am surprised QA can't reproduce this, over 50% of fights I do end up crashing, usually bigger ones with more visual effects where the game lags a bit and usually while casting a spell with visual effect. Any fights with multiple characters and a few environmental effects life fire, electrified water, steam and such will usually crash. It also seems like playing very slowly reduces the chance of crashing. So find a fight thats been reported to crash, get the most environmental effects everywhere and cast a ton of spells very quickly. Thats a 90% chance of crash on my switch. Handheld mode for me, havent tried dock mode.
If youve done all of this numerous times and never experienced any crash, I can see 2 possibilities: your QA are working on a setup different than us (not a basic switch or something) or the crash occur only on certain other unknown conditions possibly unrelated to the game like the amount of space left on the switch, some other games installed or not or whatever other weird interaction.
