From my experience in jams (5+ now), It's generally its okay to update your entry to fix bugs during the voting period. In other words: If something is making your game unplayable/buggy, it is okay to fix it as long as nothing new is added. It is generally not okay to add additional features/content/sounds/assets while the voting period is going.
I'd ask HeartBeast if you want to know officially. What I said is just from my experience, not the rules for this jam (and until we know officially, I would assume we cannot update during the voting period, to be on the safe side)