Driver Window Help????

My 2007 Ferrari 599 has an intermittent problem - my local (independent, but Ferrari competent) shop is stumped, so I'm looking to see if anyone else has encountered the same issue - or can point me in the right direction?

On startup, the window will go up or down using the switch (normal operation). After about 5 minutes of the car running - the window is now stuck in whatever position it's in (if it's down, it will not go back up - if it's up, it will not go back down).

At this point, if you stop the car and turn the ignition off (and let the car completely shut down - electrical system as well) - it will reset and the window will be operable as soon as you re-start the car - for roughly 5 minutes - before becoming "stuck" again.

Thanks in advance for any help or suggestions!