Emulator

Can you reproduce this bug without using a save state?

Yes. I captured the save state because it always crashed, it's not a broken save state bug.

After Dolphin crashed, I reloaded the save (using the in-game load) and it kept crashing at the same point over and over. I gave up after the 3rd time (I captured the save state right before it happened the 3rd time just in case, and was right) but you can work around it by levelling the character to class-change using Bonus Experience from the Base menu instead which won't crash Dolphin. [Only affects Sigrun, other characters don't seem to cause it]