My 300E did exactly the same thing ... stalling on the first deceleration after getting warmed up, after that it was generally okay. It always restarted without any problem. It is almost as if the computer lets the idle drop too low for a split second on deceleration, allowing it to stall.
There is a whole laundry list of things that have been known to cause stalling problems on this car ... fuel pump relay, OVP, flywheel sensor, etc. ... if I can find the thread I'll copy it for you. But again, your stalling problem sounds exactly like what I had going on ... although logically it should affect your cruise control.