Okay, follow-up.

Took an 800 mile round trip to actually be bored enough on the road to really track it down:

Pass' Window, Front Vertical Edge Interior, Right at the top. (Last finger-tip width below where the top of the 4' of straight-Vertical rubber seal meets the angle of the uppward sweep.) Tiny buckle/buldge in the seal. Shouldn't be too big a deal, now that I know where it is.