Strange behavior

Over the last week we have done several partial promotions from our DEV IS 6.01 to our QA IS 6.01 … and are noticing a strange behavior. Some services have code from a completely different service. For instance, my service ABC seems to have code from a completely random service XYZ. It is as though someone went into service XYZ, did a select all-copy, then went into service ABC, and pasted all the code from XYZ into it.

Any way this could be anything besides a developer screwup? In other words … could this be a promotion related issue?