I finished my random dungeon and got my Ardent Flame subclassed skill line to 42...

From there I spend 2 skill points on Inferno skill... taking me from 30 points to 28, because you see that Inferno is now available for purchase...

And I travel out of the dungeon and back to Vvardenfell... only to find my skill line has regressed back to level 39, and locked out the Inferno skill from me, even though I'm now short the 2 skill points I spent on it....

Can someone please explain??