Gen2 Backseat Rattle

[rockymtnraptors]

New Raptor owner here looking for help on what anyone thinks this rattle sound could be. I have checked the rear seat belt, door alignment, and did the TSB on the moonroof. The rattle sounds like it is coming from the seatbelt pillar, but when I took it apart, I was unable to find anything loose. Has anyone experienced this before and or does anyone have any thoughts?

 

[New recaros]

I have that also, I think it may be the passenger side rear door. But I really don’t know