2015 gr. jeep cher. loses power when making right hand turn from parkinglot to road. any suggestion?

ive had my 2015 grand jeep Cherokee in several times. when making a right hand turn from a raised parkinglot/driveway onto the roadway, it stalls for a few seconds as if it loses power. dealership said they guessed by ("claiming") they replaced the VALVE BODY and then performing an update to transmission control module. it stopped stalling for maybe two weeks and then returned to stalling again. so i took it back in today. they said even if they can get it to happen again (which it does regularly) they wouldn't be able to make a repair as they "don't know" what the problem is and therefore cant repair it. ?? they said they wont "guess" anymore. they told me the valve body is the bottom of the transmission. I told them I did some past research showing some sort of air intake "valve" or "body" something could be the problem. they advised me this item is at the top of the transmission and contains some sort of sensors???? they are unwilling to make this replacement as it would be a guess. I'm concerned the valve body had something to do with it as it work for a little. wondering if they never replaced it but said they did and just put a temp. band aid on it ? anyone else have this problem or suggestion on what the problem might be?