HOT START SOLVED!
Thanks for all the suggestions and posts.
The culprit to this hot start problem anyway was the fuel injection nozzles. When they were all replaced. all the drivability issues vanished.
This 124 is an '89 300 CE with only 70K miles, previously driven for most of its life by an older lady, who probably didn't know what full throttle was. Use it or loose it, is what the technician related to me.
Kudos goes to Brooklyn Motoren Werke in Brooklyn, Wisc for their efforts!