I've beaten Steven Fright on master difficulty in a 1v1 skirmish three times now, and the game won't give me the associated achievement. I've beaten every other AI personality on master difficulty and gotten credit, but this one just isn't registering. Other achievements, such as the Heart of Gold campaign achievements, still seem to be unlocked normally so it's not like I've lost the ability to earn new achievements.

Another weird achievement issue I had that may be related is that I was recently awarded all My Pet Dungeon achievements even though I've only completed the first level. This happened when the game was launched, and was just a sudden flurry of achievement notifications. I had beaten every Master difficulty AI other than Steven Fright prior to this occurring, so it's the only thing I can think of that may have changed between beating the others and beating Steven Fright.

Anyone know what may be going on, or how I can fix it?