When load play scene at first time all works. But if i for example return back to main menu and load play scene again some stuff don't work, saying that objects were destroyed but all of them are in the scene and are attached to classes. Some of them don't really have dependencies between each other. For example Audio Manager works with events only, so other scripts just have to call events with no attention to Audio Manager missing parts.
P.s.
- I check events for null.
- I tried to somehow "unload" scenes before loading new one, so next time loading it will be like first.