I noticed some have had software updated and this resolved the problem (I believe mine has the latest) but I can't wrap my head around the fact that somehow software can go "bad" all else being the same and then there are those who had the transmission replaced. I can't believe that it there isn't something mechanical going on to cause this. Coincidentally, I did receive a recall notice with the following items the other day but a check says mine has been repaired S25 Reprogram Powertrain Control Module, S55 Transaxle Range Sensor Wire Harness.
Software doesn't go bad. It has bugs or it doesn't. When firmware fixes something, it means either they missed generating test cases for all real life interactions of the many systems and algorithms in the vehicle, or that the parts providing input to the software are not what was assumed or in spec, or that assembly or real life operating conditions generate more slop or tighter tolerances/clearances than presumed when originally writing the software.
For example, i got hit with the very early "improbably value" error for the transmission. According to FCA this was due to a sensor producing values outside of the expected range. The two choices were that the sensor was defective, or they developed the code for different behavior than the production sensor actually exhibited. The end result was they updated the software to not be confused by the sensor output values, and everything works normally.
Another example was that I would sometimes get a cold start lurch where from a cold start, I'd apply throttle, get very little forward motion, and then SLAM things would engage in a neck snapping way. This was an example of the software logic being a poor fit with reality under specific circumstances. This would not happen if you backed out of your parking spot in the morning, because whatever was going on was done by the time you shifted into a forward gear. This wouldn't happen if you parked at the curb and took off like you stole it, because in that situation more than likely a different algorithm or strategy was chosen for the throttle, transmission, or AWD system, and you didn't get the convergence of behavior that cause the problem.
However if it was cool out, you parked curbside or otherwise went immediately into forward motion with moderate acceleration and staying below 30 mph, the vehicle would pull throttle input temporarily, you would likely try to give it more gas which did nothing, then it would stop pulling throttle and suddenly you are giving it the beans (or at least it's finally responding to you doing so) right when it's decided to lock up the dog clutches in the AWD system or in the middle of a shift expecting the throttle value to not change mid shift. Not sure which. But the result as someone who has to park curb side a lot was that fall and winter, I'd have a 50-50 chance of the thing being really sluggish and then WHAM!
Once they updated the software to avoid that as much as possible, it went from an every other morning problem or more. To a couple times each winter. Likely because they can't tweak one subsystem's behavior enough without negatively impacting a strategy that prevents significant wear, or because pushing changes to exclude the possibility entirely means they could be impacting the projected emissions of the vehicle in a way that could get them in trouble.
There was a VERY nice version of the firmware that shifted really well and got decent gas mileage. I miss it. I suspect it impacted emissions though as it went away with the first firmware update after FCA started being investigated for emissions tampering in software.
I suspect the 30mph groan is an example of the software can't cope with hardware tolerances as delivered. At least if you believe the one forum user form Italy that says they were able to fix his problem, but it required FCA engineers to come out and essentially drop a custom firmware on the vehicle with calibrated behavior in unlocking the clutch in the rear drive unit. The groan doesn't happen in 4wd mode because it forces it locked. IT doesn't happen in really cold weather for a lot of people because that changes the AWD engagement algorithm to using a different strategy for when and how it engages AWD. It doesn't happen over ~4xmph because around 50mph the AWD is forced to be disengaged for highway fuel economy. It doesn't happen when you disable traction control likely because they are doing something with prepping the wet clutch so that it can cope with wheel slip faster with TC on. But they likely can't ride that line without issues due to variation between units without either getting so lax TC doesn't work right, or going with the more aggressive cold weather algorithm, which would likley lower fuel economy and mean they were changing something their EPA emissions estimates were based on, and that last bit is a no-no.