How did water get there?

The seam between the quarter and the deck filler between the trunklid and the back window is leaded in on convertibles instead of just having seam sealer like a hardtop car. I've never looked at a hardtop and sedan side by side to see what/if there was a difference in the deck filler panel. That piece is good on my car. The drivers quarter got side swiped at some point in its life and also had a limb fall and whack the top of the quarter and on top of the conv trim. That's gonna be a head scratcher to fix! :BangHead: