Aft Prop Shaft Seal Leak

Dear forum experts,

I have had a small oil leak (pretty much since engine was new) at the aft part of the prop shaft. There is a seal there that was changed three times with various Loctite applications/brands but the leak keeps coming back. When looking at the gearbox casing we noticed some deep marks (top and bottom) that look like tooling marks. Are these normal?

Lately Rotax suggested to change the propeller shaft, I suppose thinking that perhaps the shaft is not up to specs, diameter slightly on the small side I suppose?

Any opinion on the matter? This should normally be covered by the warranty (since leak started at about 20 hours and a month after taking possession of the new LSA) but I don't know if the proposed fix will address the problem.

Thanks.

Best regards,

Jeff