Earlier today, I encountered a game crash in the Skull Ganon fight during single-player Symphony of the Mask mode. Unfortunately, I was unable to record the error or use the Switch’s video function.
I had finished the second phase of the fight while walking onto the leftmost Triforce tile that appears. I skipped the cutscene entering the third phase, then found that the beam of light which normally gradually becomes larger immediately appeared over the tile at full size. After two beats had passed in this state, the crash occurred. My attempts to reproduce the crash have not worked.
The seed I was playing on was 4114264605, and this was my first attempt against the boss on this seed. I believe that all of the other enemies had been cleared at the time of transitioning to the second phase.