Coming late to the party. Your teminology is quite different from here so didn't quite catch all of it.
Just wanted to add the safety devices themselves can fail and do. Circuit breakers can go partially bad as well as totally bad. They can get wishy washy and trip at lower levels then they should.
If you had something honestly taking out a breaker, and then removed/fixed the problem taking it out, it might have damaged the breaker, or just pushed it over the edge of age/use breakdown.
