Advanced key affected by heat/humidity?

I bought my MS6 last September, and the advanced key worked fine until this spring, when the button on the trunk wasn't responding. After 2 visits to the Speed dealer, they fixed it. (The first time they replaced the latch because the geniuses didn't know what I was talking about. Once I dragged them out to my car and showed them the problem, they fixed it.) Everything worked fine until the end of June...

At first, I couldn't figure out what was giving me problems. The buttons on the door handles would randomly not work. Then they would work fine. The red "KEY" light on the dash would sometimes show up. I replaced the battery in the fob, and it was fine for a couple of days. (The car came with one complete advanced key fob and one key that slides into a second fob, but not the fob. Dealer told me $400 for a replacement. No valet key came with the car.)

It seems that when the car sits in the sun or gets hot from driving, the buttons don't cooperate. IE - I'll unlock the doors with the buttons in Boston, drive on the pike, stop at a rest area in the Berkshires, and the buttons won't work. Or they'll work in the morning when I leave for work, but not when I am leaving work that afternoon. The light on fob will flash while I'm pressing the button on the door, but the locking mechanism will not do anything. If the temps cool down for a few days and I'm not doing any long driving, everything is fine.

Anybody run into this? Any chance of this getting fixed? I have not changed cell phones or where I keep the fob in relation to the cell phone etc. And inserting/starting the car with the key from the fob does not placate the red "KEY" light on the dash when it appears.

Another note - the problems in June appeared a week before the 4 yr/50K mile warranty ran out. I was out of town for work that week, with the car. I called and spoke with the service department of my dealer of choice, but they didn't have many ideas as to what might be the problem, other than to replace the fob. When I got back home, the problem had gone away (since the temps had dropped to the 70's, not the 90's, but I hadn't yet figured out that was affecting things). Since I called and complained about the problem prior to the warranty expiration, is it possible they would still cover it under the warranty?

sounds like sensor problems to me.
the sensors used for detecting the fob may be going bad, one, some or all perhaps.
Just a fluke perhaps, i have only heard of one other case of people's advanced keyless entry giving similar problems.

ended up being the driver side sensor was going bad, replacement = no further issues.
So have them dig those sensors out for diagnostics, tests and perhaps replacement.

GL meng, that all sounds fustrating but i hope it works out!
cheers

mine stops woring on a regular basis... i've had my trunk and drivers door request buttons replaced, my drivers door is still intermitent and my key itself is iffy in this weather...

however i also find that my smartphone also interferes with the smart key

Its doubtful that the heat affects it, but possibly the humiditycould. Its sounds like a faulty antenna. Mine did the same for a while till it completely stopped working.Turns out the antenna was corroded. The humidity could accelerate corrosion.