I haven't got an exact number, but if there is, I assume is below 19 (I deleted 44; it's a bit a pain in the ass to remove trigs as I work mainly with prefabs and have to do edit them 1 by one lol). And that is weird and I believe impossible, because I'm sure that more than 19 work at the same time, as I've been testing pretty much everything everytime. The exceptions are those 3-4 rebel ones, which I also tried remaking from scratch, with same result
Tried deleting all of the models (800+) and a huge amount of prefabs (800+), but also nothing haha. Could be maybe script_brushmodels? I have around 30, but some of them are groups of much more brushes.
Guess I will have to rethink another workaround or idk
Edit. brushmodels either, deleted those huge groups, same thing hahaha