Is it the entire plastic piece or just the decorative edging? Get it fixed under warranty. If it is the entire trim corner, just push the clip back down.
The trim corner is a seperate piece and when I push it down, it just pops back up. Looks like it must have lost its shape somehow. Definitely something you wouldnt expect in a new car.

One thing Im hesitant about when taking things back to dealers is that they may try to fix something but ultimately bodge it up even worse and then hide it.