Stock except muffler delete and a drop in K&N air filter, if that even counts

Last fall, around 30,000 Kms (18,000ish miles) the car developed an extreme Shudder or vibration while travelling at 50 km/hr (30mph) when you would increase the throttle to less than 1/4 pedal approximately. Best I can tell the car would be in 3rd gear and then lock the torque converter just prior to this happening. Increase the throttle and force a shift, problem disappears.

The dealer flashed the newest software into it, test drove it, and said it seemed fine. Nope, I requested to take the on a drive to show him exactly what was going on. He was very surprised and said he had to think / do some homework on what possible items could cause this.

Next day, the dealership reports back and says they found info of an identical complaint on an identical 2014 R/T AWD in Quebec. That car got a new rear end, no change, new driveshaft, rubber something possibly, possibly axles, no change, third attempt, they replaced the torque converter, problem solved. So the dealership says they are going to jump over all these items and go straight to the torque converter. They did, problem solved, weeks later I parked the car for winter.

The car has been fine all spring and summer but recently it seems the problem MAY be returning at 42,000 kms (26,000 miles). Under the same driving conditions as above, the vibration is mild and much harder to replicate. I do notice however that when I can get it to do it, I think I am seeing some fluctuations in the tach of maybe a 100 rpm or so. Seems like a slip rpm problem or valve body based on experience from years ago on my 2002 Monte Carlo SS which I had ZZPerformance install an HD trans with 2.93 gears and a 3000 stall converter. While that car didn't shudder, I did see the tach "float" over 200 rpm under light load. It eventually cooked itself based on my trans gauge temp and when the entire trans was replaced with another, the same problem remained. A few weeks later, got it figured out that the PCM needed a change to the "TCC DC MIN" table IIRC. No issues on that car since.

So my questions are:

Has anyone experienced this, what was your fix? I kinda wonder if it's even specific to the the AWD models maybe.
Is there a simple table change that could possibly fix some fault that Dodge has in the OEM PCM?
Do I have a lemon?

I have 30 days left on my warranty and would rather not be replacing torque converters every other year after 10,000 kms (6,000 miles) of driving.

On a side note, this is the first Dodge I have ever owned. This thing seems to even shift at a slightly higher rpm that it should under light load, and when it does, you can feel it. On decel its worse, almost bangs itself down through the gears when you are slowing down.

Thanx,
Krunch