In a quick test, they stopped working (and that's logic, because i don't call parent::buildLink)
second scenario which also not worked:
add-on 1: overrides the match method
add-on 2: overrides the buildlink method.
problem: the code of add-on 2 isn't called
if i implement the buildLink from add-on2 into add-on 1 it's working, but having 2 seperate routes doesn't work.
Hope you know what i mean