Taken from Schnellfahrstrecke Köln-Aachen Route with the ICE 3, scenario 5 "ICE and rain" of the 1st chapter of the journey. Tried a second time and didn't happen again. Weird. Link to Image: https://imgur.com/a/MKikHFY
IIRC your character sits higher, but only on the ICE is noticeable from the outside because the cab is smaller or maybe they fixed it
Then it has to be fixed or it is a rare bug . I've just tried it again in Cologne-Aachen and again I haven't seen anything unusual.
You also have to be in the correct position as well as crouching It works in the talent as well but it's harder to do Might be different on PC