2012 CX-9 Transmission Shutter after fluid flush

Had my Transmission serviced about a month ago. Started to notice a shutter when shifting into 4th and sometimes 5th gear. Took it back to the shop that serviced it and they tried Mazda fluid. Did not fix the problem. Any ideas on what the problem is. Car has 69k miles. Never had a problem until I had it serviced
2012 Mazda CX-9 Grand Touring FWD
Does this shop know the correct procedure to set/check the level. Search this forum for it.
I had an awful torque converter lockup clutch shudder on my 2010 CX-9 with 130k miles. My transmission guy said it was the worst he had ever seen in his 40 years of working on transmissions. Fortunately the fix was relatively simple - I did multiple drain and fills of the ATF until the drained fluid came out almost like new fluid then added a tube of friction modifier (I forget the brand name, it was a red tube labeled “Shudder Fix”). It worked perfectly after that. If you’re trans was just serviced, I’d check to make sure it has the right amount of fluid (and that it’s the right color) then add a tube of shudder fix
2008 CX-9 Grand Touring
OK - I've got somewhat of a similar situation. The car "shutters" around 40-45mph and again at 60ish. After some time at 70mph, it seems to lighten.

From reading this - I'm thinking torque convertor. The Transfer Case was replaced 2 years ago, maybe 30,000 miles.

Anybody think the fill/refill/ add stiction will work.... or maybe just add stiction?
That sounds pretty similar to my situation. It would shudder the most when cruising then applying just a tiny bit of throttle, either to speed up or when going up a shallow incline. It felt like the car was going over rumble strips even if the road was perfectly smooth. Getting off the gas or pressing down to force a downshift stopped the shudder until the next time the car was in a shudder-prone situation. Also, it never shuddered when in manual mode. That makes sense because manual mode forces the torque converter to lockup all the time, thus eliminating it from the equation.

I first tried adding just the tube of friction modifier and it helped a little bit but it still shuddered like mad. The ultimate fix was multiple drain and fills plus a tube of friction modifier on the final fill (so it wouldn’t be diluted out over the course of the drain/fills). I’m pretty sure the previous owner never changed the fluid so it likely had ~160k miles on it. Needless to say the fluid was really nasty and I ended up having to do 6 drain/fills before it started coming out red again.