This has already happened, several times. It's kinda funny, but it should really probably get fixed.
commenting to add a specific case: the automatically chosen capitalization for the series "Chainsaw Man" is "Chainsaw man". even ignoring that i'd prefer it to be lowercase, that's basically as bad of an option as you can get without capitalizing it poorly on purpose. would love to be able to change that
honestly, why is "canonical capitalization" for tags a thing to begin with? what purpose does that serve?