On my last project (vs2017) I goes from debug version to release to debug and the break point didn't work anymore in the last debug version. I had to deselect manually "activate only my code" and everything came back to normal. I really If I understand that the passage to release toggle it automatically, I don't understand why to come back to the debug version don't untoggle it automatically. Maybe it is the same here?

by the ways, Sometimes, instead of a break point, I put a stop or messagebox (or console.write or debug.write) with the value I want to check or just "test" to check if it goes there.