https://www.youtube.com/watch?v=izK2I8K7AZM
These random splits might be due to me running any% easy, but probably still worth investigating. Below are timestamps for the video, not the run itself:
~19:50 There's a frame in Zazabi's room that gets split, right around jumping to the highest ledge in the room
*this happened to me twice; once in this video and once in a dead run
~1:02:50 The power bomb expansion after the sector 5 SA-X sequence gets a split. Good for 100% but for any% most runners probably avoid this one.
~1:07:55 Missile expansion in the reactor silo gets a split. Again, good for hundo, not so much for any%
~1:34:55 There's a second frame after screw attack that gets a split, resulting in a premature PB for me

Aaaaaand that's everything out of the ordinary that happened to me. It's a lot of work, I'm sure, but I imagine the finished autosplitter should have checks for each expansion in the game, mostly for 100%. What I think would be really handy is a split upon freeing the animals in the habitation deck; I see lots of runners have a split for that.