This keeps happening by default. Is this a bug?
I’m not seeing any collisions.
Corrected! I uploaded the wrong file.
To add to that, accent marks are colliding with tremolo lines
As Dan already said in your other thread How do I flip this rest? - Dorico - Steinberg Forums, you seem to have stem-up and stem-down voices the wrong way round, and then tried to fix the problem by overriding the positions of objects. For example the tremolo on the first note should be below the note not above it.
If you use voices correctly (i.e. the top notes are stem-up and the bottom notes are stem-down) you probably wont get any of these problems.