There is a plastic rattle coming from either the passenger glove compartment area or somewhere behind the dash. This wasn’t happening until I started going over bumps in the city. This is not a strut rattle but something dash related, if anyone has figured something similar to this out please let me know.
2013 rdx.

 

Easy / obvious checks are the removable shelf in the glove box and/or the cabin air filter door.

 

I bought a '14 RDX Tech in Feb and started noticing a similar rattle. For me, the solution was to tape a small (1/2" or so) roll (or wad) of electrical tape along the top of the inside of the glove box. It seemed the glove box door was a little loose, and I couldn't easily figure out how to tighten it, so went with this low-tech solution. Has worked fine but of course, no idea if this is what's causing your problem.