If you pulled the front cover to add the kdp fix and did not have the installation sleeve for replacing the front cover, chances are that you folded over the front seal lip. I did the same and ended up buying a new seal, removing the cover a second time and reinstalling.
I was surprised at how difficult it was to get the seal started over the crankshaft. Without the supplied installation sleeve, it would be difficult.
About $50 and time to correct your problem.
If you did the external kdp fix, your guess is as good as mine but do not see how they would be related (external kdp fix and front seal leak)