NC MX-5 — what's up with this window seal?

[MajorMantra]

I viewed an NC 3.5 yesterday and I'm considering buying it. I was a bit confused as to what was going on here:



This is at the bottom of the 'quarterlight' window trim, a known rust spot I believe. It looked like this on both sides, with the little seal/tape thing sticking out.

Can anyone help? Cheers!