The car is a BMW automatic diesel from 2013 with the zf 8 speed tranny. After replacing the timing chain and cleaning the intake manifold 2 years ago it started exhibiting hard shifts, worse when cold, better to perfect when warm.
When cold: all gear shifts can be felt, 1-2 being the jerkiest and more smooth as the gears go up at either slow or hard acceleration. It gets better with driving but also if shutting down the engine for 10 minutes and restarting (in the.morning when engine is cold)
When warm I can feel a slight push from behind when shifting 1-2 at very very slow acceleration.
There are no errors on the tester software, transmission fluid has been replaced, it was in good condition.