WELL! I was getting ready to file tickets to Django, `model_bakery`, all of the repos of my dependencies because of everyone else's buggy code..
Then I took another look after a night and, well, the call was coming from inside the house. 😳
I was setting the relationship up on the wrong side of the equation, on the other model, not on my model where it's actually defined. Still don't totally understand why I could access the related fields directly, but not query for them..