I found a bug
When I went to level up from HR 35 to 36 (at Nocturna), my max HP and SP declined.
I was at 3825 HP and 1525 SP (I was planning to shred Dorian once I hit 5K HP and 2.5K SP) but trying to level up to 36 HR knocks my HP to 2385 and SP to 1038.
Fortunately I saved before I went to level up, so I was able to reload the save, but now I have all this material to level up with that I can't use.
I'm going to see if the same bug exists when I try and level up with Maahlda at the Castle.
Edit: Yup, same issue both places