1) using rapid debugger /especially after longer sessions of debugging/ I'm facing situation where rapid do not show exact place of problems - switching to legacy usually solves problem.
2) sometimes my project can not start (connect?) in rapid mode /works in release and legacy - but not in rapid/. Sometimes cleaning helps. Sometime cleaning project seems to be "not enough" - then I switch to legacy or release and try come back to rapid (saves my time > Ctr+S) - sometime works, sometime not - hard to say why (reproduce).
I have two bigger projects / not too big- just: 5 services, 8 code modules, 5 activity modules, 8 class mod, 26 libs/ and the problems usually happens there.