I think it may be an issue with the seal material itself.
I've seen versions where the rubber is slightly convex and comes out of the gap by a small amount, has a slightly raised profile above the line of the panels and also spreads slightly wider than the gap underneath.
I've seen other versions where the rubber is slightly concave and the centre of it sits just below the line of the two panels and the edges sit exactly with the panel edge, so it only just fills the gap.
Here's the Seneca Blue press car BVE (a nearly final pre-prod car) at Sunday's Hendy dealer event, which I think shows the concave seal:
View attachment 7707
Pic: phil flash on TLF