My 1D Mark IIN is no stranger to weird behaviour, but this is the mother of all its mood swings. So I need some help before I decide either to take it to the Canon service again or kick it out the window.

About a month ago it started doing the following:
- in Av or Tv mode with AF on the shutter release and AE lock on the AE lock button, it locks the exposure when it locks the focus. Therefore, when the light changes, the camera doesn’t change the exposure unless I focus again in new conditions. Pretty awkward when shooting concerts.
- when the AF is on the AE lock button and the AE lock is on the shutter release, it would be normal that the camera would lock the exposure when I pressed the shutter half-way. But of course it should stay locked. Well, instead the camera keeps the exposure locked ONLY while I am pressing the shutter release half-way. And the AF lock (when on the AE lock button) works fine now and doesn’t lock the exposure.

And the solutions that didn’t work so far: resetting the camera completely. All CF functions, all personal functions, the whole nine yards. Nothing happened.
Went on to reloading the firmware (hope dies last), and … well, I guess everything dies eventually. :) Surprise, surprise, no difference.

So what now? I’d really appreciate, if anyone has any idea or had the same problem.
I thought my shutter release is faulty, but I’m afraid this kind of mess is a lot more software based or something. Come to think of it, it’s only the shutter release that’s behaving strange. Locks exposure when it locks the focus, and locks the exposure only when pressing the shuter release half-way… I can’t seem to find the pattern, although it’s only the AE lock thing.
And another fact. In Servo focusing mode, it doesn’t lock the exposure of course, because it never actually locks the focus…

Hope anyone knows what to do. (Other than commiting the mental again :)) Maybe I’m just missing something here…

Thanks, everybody.