Polymorph wizard spells.

[RaiderOne]

I'm playing a half orc with Int 17 and a +2 ring for 19 total. When I polymorph and turn back I lose some prepared spells as normal, but then I have an extra 6th level spell slot to prepare. I usually only get 2 but it gives me 3. The extra slot work as normal through rests etc, and is only removed if i remove and requip the +2 ring.