Inner axel seal leak?

Put the 68B up on jackstands to get ready to do some under body work and to pull the differential to make a gear change and found oil on the inside rim of the L rear. Also then found a drop of gear oil on the outer axel flange.
The axels were coming out anyway to be able to remove the diff, so that is no extra work.
This is a green bearing set up with bearing and axels from Dr Diff.
The seals were new when it was assembled probably 8 years ago, but till last year was a drag race only car, I turned it back into a street car last year, so actual driven miles are really low.
Is the inner axel seal the only thing that contains the gear oil from leaking out on the ends? Any common reasons why they start leaking that I can address when swapping them out?

There is only the one inner oil seal the 8 3/4 uses. Its a simple one to replace. try not to let the axle ride on them when your putting them together.

Some possible causes;

The seal has a spring tensioner, it can pop out of place when installed. (I coat them in axle grease to help them stay in place when tapping the new seal in)

Seal damaged during installation and / or installed with the wrong side out.

Seal cocked in the bore.

Axle weight left on the seal lip during installation , removal or left hanging loose during a center gear set swap.

Nothing lasts forever anymore...my ex can confirm that.
Things just wear out.