You don’t use the definite article after the word nästa, it’s weird, but that’s how it is.
Rather the other way around in that case, nästa will always precede something indefinite.
If nästa is definite without the ending then the hint should reflect that. If it's ambiguous then shouldn't "next level ..." be accepted? Either way it seems like something is wrong here ...
It's accepted withough the definite article when translating EN->SE. As for the hints, they are just hints that show the possible meanings of a word.