Dct upshift automatic in manual mide

[kninjak]

2012 zcp
Evolve tune for test pipe and Dct since 3 years.
60k miles I am second owner bought the car at 9500 miles. Only problem very early for brake booster done under warranty around 15k
I checked the battery for voltage n load at Napa n auto zone. Battery checked out good still holding 90% charge .
Since a week when I drive in manual mode some time the car shift back to 7th gear from 6th or 4th from 3rd.
Somtime the rpm on down shift don't move. So far no code or chk engine light.
Droping to dealer today for airbag recall n they will do complimentry car inspection to see every thing is ok.
I haven't told them about the dct issue yet let's see what they find
N e thing I should look for
N e help appreciate it

[Helmsman]

I don't know how the box start to behave if fluid level is getting too low but might be worth checking if you have the infamous leak going?

[bmwfst1]

I agree. The trans does a lot of weird things when low on oil with no warning lights

[OzCoE92]

Are you still running the original battery in the car? If so, that maybe one of your issues, things tend to go haywire when they are low on voltage. Have you received a battery discharge warning in the car at all?

[kninjak]

No battery discharge warning.
No transmission fluid leak i opened the transmission cover no leak on the pan just 1 corner had oil around the rubber its been same since last 3 year.
under warranty i showed to BMW dealer according to BMW NA it a seppage and not leak as no oil is on the pan or around the trasmisson according to them its normal

It is still the original battery the voltage is 12.7 when it been sitting overnight and 13.7 when car is running