During a BG Duos match, playing as Genn, Worgen King, I picked Souvenir Stand after which I picked Felburned Ledger. I was playing Demons and had picked “Spells give +1 Health” once earlier via Intrepid Botanist.
On my board was also an Ashen Corruptor.
As soon as I picked up Felburned Ledger, the spell power health stat bugged out for that round.
https://i.ibb.co/SDzkrHgG/Hearthstone-Screenshot-04-20-26-17-45-43.png
Then, the next round:
https://i.ibb.co/d0L18hgb/image.png
And after playing several minions, the amount + tooltip (not visible in this screenshot) both normalised:
https://i.ibb.co/n8wC8sCp/image.png
Not sure exactly what caused it, but I think this is all the relevant information. It didn’t happen again after that, but I’m sure you guys can simulate my conditions to try and reproduce it.