This is an old topic, but I experienced a similar issue. Currently using UE 5.2.
I have a variable on my camera component (full BP) that is marked as private and not instance editable (this is the follow target actor reference set through a function). When I start the game, everything works fine. Then I select the camera instance (during runtime) and change its location manually. After doing this, the variable mentioned above loses its value (I assume it resets to its default, which is null/none).
Marking the variable “instance editable” solves the problem, however it is not the desired behaviour, since I do not want this variable to be instance editable. 