That looks like the piece that is attached to the frame near the rear exhaust hanger,back by muffler.
it would be used to hold electrical connectors.
I had to remove this to install my Rock Blockz mud flaps.
Did you ever get this resolved?
I have a 2021 Mojave and getting exactly the same sound.
Dealer seem to think its brake caliper but I'm not convinced that is what it is.
Just want to explore all resolutions before they start randomly replacing parts.
Thanks in advance.