Is it only in one geographic location that they act odd... or did they act odd at the dealership as well...?
I only ask because I found with my LAST car... there were some days here at home that no matter WHAT I DID... I could **NOT** remote-start my car... from every window, door, angle that I could try... it would not work... but MOST days it worked fine... as if SOME days, there was some sort of local interference messing with the signal between my FOB and car.
Most days, I could double-tap the button from ANYWHERE in my house and it would work flawlessly - didn't need to be near a window or see the car... could even do it from the basement.
But those very odd, rare days... there was NOTHING I could do to get a signal to it. I just chalked-it-up to occasional "interference"... but not sure if that has anything remotely to do with YOUR issue(s).