5.5.3 Bug? Compiling a class that is used as a parameter in a blueprint library function causes the library to change on disk

[hard_code]

I have a Vehicle blueprint and a blueprint library with a function that takes a refrence to the class Vehicle. Whenever I compile Vehicle the Blueprint Library needs to be saved. When I do a perforce diff of the library blueprint in engine there are no changes even though perforce wants to check it in.