Yes. It is not the "delayed upshift" (delayed to heat catalytic converter) function. This problem occurs when the transmission is still cold but not during the first few shifts. It happened again this morning. Something I noticed then is if I let up on the accelerator when it is doing this it will then shift as it should. If I don't it will continue to act as if it wants to shift but won't. Could this possibly be a vacuum problem?
I have taken this car to two dealers and several independent mechanics and they can not figure out what is wrong. I have also asked several MB techs and others that specialize in these transmissions - they have not experienced this and don't have a clue either.