It seems to have improved a bit. By no means is it perfect. I test drove another 2014 e class and it shifted much smoother. Mercedes said it could take up to 2 weeks for the adaptations to learn.
You're lucky they were honest in admitting they have no idea what it could be. It gets expensive when they decide to throw parts at an "unknown" issue. I highly doubt 2 weeks of driving is going to resolve the hard downshifts.
Have you by chance checked your motor/transmission/rear sub frame mounts?
They still think it's software related. Going in for manual adjustments to the adaptations in a week. Yeah shocking. They are being really good about it for now. They're not going to charge me for the manual adjustments. If that doesn't work then I dunno. Maybe swap out the valve body. The service manager confirmed there were no transmission services in the first 70k so I'm the first one to find the issue.
No I have not check the mounts. You think they could be related? I've narrowed down more when the hard Downshifts happen. The worst downshift is 5 to 4. Tested it out today in manual. Driving about 60km/hr in 5th gear, step on the gas pedal about 1/4 depressed then downshift to 4 and I get a big jerk. The rest are not that bad, although Downshifts that pass down through 4 often have a jerk-hesitation-then acceleration. When driving very gently, all gear shifts are butter smooth. Downshifting while accelerating is a bad.
I was reading about "Peter Ubers" who was dealing with some serious transmission problems on his brand new 2014 E550. I hope this isn't the same case. Because he went through two brand new cars for transmission problems.