I rounded up the old quad rings from the 950 and the 525, broke out the Macro lens, and took a close look.
This is a pretty good-looking edge that presumably was an upper/inside edge-
Here's the outwards-facing edge from the 950-
Pretty chewed up. It would seem I need to wash out the seal cup area more often.
Then there's the 525 seal-
Now THAT'S chewed!
Of course, this bike sees a lot more mud than the 950 does, as it's the one I use for Enduro course layout work, but it sure does explain the leakage.
Thanks again for all the input, guys.