It's a little annoying, but all of our cars do that. You'll notice if you pay close attention that even in "D", the car downshifts as it comes to a stop. However, in "D" it downshifts smoothly and you don't really feel it. In "M" mode the timing is different and has more jerk.
(For those that don't own one and might not understand the rest of this - the 7AT in M-mode isn't completely manual. It downshifts for you as you decelerate, but it does so at very low rpms, much lower than a human would usually downshift at)
This probably has to do with timing compromises to avoid surprising the driver in M-mode (which it still does, but they're trying). The "surprise" part that they're trying to avoid, but which can still happen sometimes, is when the car downshifts on its own a split second before you request a downshift. Like if I'm coming into a curve in 3rd, and I think "hmmm I want to be in 2nd", but a split second before I click the paddle, the car downshifts into 2nd on its own, then interprets my paddle input as a request for 1st gear. That can be really confusing. Don't forget that while in a turn, the indicator for the current gear is often obscured by the steering wheel too.
Coming down to a near-stop at a stoplight that then turns green before full-stop can be annoying in the M-mode too if you let the revs drop to the point that M-mode downshifts for you. Ends up being a lot of confusion between you and the car about what gear you want to take off in at that point.
The bottom line is that from a driver's perspective while focusing on all the other things you're doing while driving, the gear selection in M-mode at low engine rpms while decelerating is unpredictable, and therefore any further shifter input is a guessing game. The best way to handle this is quite simple: don't use M-mode for low-rpm driving. If you plan to let the revs down that far anyways, just put it back in D and save yourself some work and confusion. M-mode is for when you're *really* driving, in which case you'll be keeping the revs in the 2k+ region (at least
), and the car won't interfere or downshift on its own.
What I'd love to see, if someone like UpRev can pull it off, would be an ECU mod that doesn't allow the M-mode to downshift for you, avoiding the confusion.