Could be caused by dirty or faulty solenoids.
According to Walky__Talky20: "I believe there is a way to recode the transmission for slightly different shift points. As it is, our tiptronic transmissions have a learning mode: if you drive aggressively for a bit, it will switch to the sportier shift points (delayed). If you drive all slow-like it will switch to the granny shift points (early). I believe there is a way in
vag-com to recode it so it starts in the sport mode, which you may like better.
Also, I feel like I am downplaying your complaint a bit here: brushing it off as a minor preference issue with the shift points. If it is obvious to you that there is something very wrong, then my advice isn't helping (what else is new, eh?).
First thing to do is check for codes in the TCU. Next thing would be to verify proper
tranny fluid level, and correct
tranny fluid type." but according to Somebody5788: "It's most likely wiring to the
solenoids in the transmission. Went through this on a tip
Jetta. Ended up replacing a
solenoid and the wiring harness internally only to find out it was part of the external harness shorting. Get it to a good shop. "