I was playing a run with a ring of luck and a warrior. By the time I defeated the king of dwarves I had a +3 armor increased to +4 with the warrior seal.
Once in the demon levels, I got lucky to receive a +6 armor drop and transferred the class armor to it.
I was expecting it to become a +7 when transferring the class armor due to the additional level of the seal, but it was transferred as a +6.
Would this be a glitch?
Agree that this makes the room much more interesting, and having a choice always is better so you don't depend purely on luck. A very welcome change.