Same thing again. Alloy flaking on wheel inside and outside, wheels look horrible and same thing happening on the inside of your rim, this causes the bead or seal over time to be compromised. On comes the low pressure light. Put air in and your good for a while but it will worsen over time to the point the tire needs broken down and rim cleaned/sanded and resealed.

I've read that filling tires with Nitrogen can reduce this problem but have not tried this.