Is the extreme expansion of the brass an indication of too high pressures and should I not use this amount in the future?
The brass always expands as much as the chamber will let it. What happened here is the chamber expanded as well and then relaxed back onto the expanded brass resulting in an interference fit. The chamber always expands and relaxes a bit, but usually less than the brass.
I'd back off on that load a bit unless you find the problem was actually rough or dirty chambers.
You might also consider saving the soft bullets for .38 special and getting harder cast bullets for mag velocities. I don't know if this is possible, but the soft bullet may be deforming too much and acting like a partial bore obstruction as the base tries to pass the nose after you touch off the charge of H-110.