I know a couple of people have already posted about their pets floating in the dance game, but that's not the problems I'm seeing.
One is the opposite: my sea dragon is sunk halfway into the ground in the dance game. Not always, but more than half the time, and I haven't noticed any particular pattern as to when it will happen.
The other glitch I'm seeing is that my spirit of nature pet, and judgement pet hatched from a spirit of nature/judgement hatch, are sometimes invisible in the dance game. As with the sea dragon issue, it's not always, but often, and I haven't noticed any particular pattern.