We’re aware of this as a known issue.
If you're able to, we request that you submit a support ticket with as much information with what you were doing right before the crash occurred (e.g., what gauntlets you were using, what in-game actions you were taking, etc.)
Additionally, any extra information about other factors such as how long your Switch was running, the last time it was powered down, may help us troubleshoot this evasive issue and aid us in patching it quickly!