[lucid21]

I don't claim the know the source of the issue, but if your car has a tune in it, I would think about that as well. To the best of my knowledge, tuning entails revising injector firing durations (at least it does on my E30 M3 tune; I have full access to the fuel map). Now what are the implications of that in terms of having fuel in your oil? I don't fully know as it probably depends on how that duration overlaps with the cylinder position, how fuel gets (or does not get) burned throughout that process etc. If that may be a/the cause, replacing the injectors will not change anything. That doesn't mean your injectors are good (not "sticky") though, which is also a possibility.