Flat tire - leaking at the rim

[1000MPH]

I've had my TE for almost 8k miles now. Coming back from a 50 mi drive and my TPMS comes on. I pull over and find my RF is at 24psi. There's no visible or audible clues so I drive a mile or so the the nearest gas station and check again. Still at 24 psi so I risk limping home (the air comp was out of order). Once home I check and it's at 22 psi and there is an audible leak at the rim. I sprayed it with water and it's leaking about 1/4 the way around, does not appear to be from the tire and no visible tire or rim damage.
I did a search for leaks at the rim and most answers were corrosion or poorly seated beads.
What are my chances the dealer will fix this under warranty? (what's so funny?)

 

[1000MPH]

The dealer fixed the flat n/c. He said the bead area was chock full of sand. How the H does sand get in there? I went off road but not up to my rims and not in sand. Hopefully this was a one time thing.
This was a much better dealer experience than my 5k oil change. I might call and give kudos.