Some ideas are:
- You branch off into another timeline and your actions make no difference to the previous timeline
- You’ve already taken said actions but just didn’t know about it so nothing changes
- Actions taken can have an effect (so you could suddenly erase yourself if you killed your parents)
- Only “nexus” or fixed events really matter, the timeline will sort itself out for minor changes
- something else entirely
Causality fracturing. Partly because observing Mandala effects. Basically causality has inertia and plasticity like matter, so soft changes bend and big changes tear, and inertial mass is also proportional to the time between the incursion and excursion points.