So this has never happened to me before, but putting the BeginPlay node into my character’s event graph moves my camera back to the default position(I just edited this from a marketplace pack). How do I prevent this?
BeginPlay on it’s own wont do that, what else did you do? 
Nothing, seriously. Without beginplay it does nothing, but with it, it does the thing.
Absolutely no idea then I’m afraid. What customizations have you made?
The only thing I can imagine is that your character has a parent class that does something on begin play. Try adding the call parent after begin play:
