Inaccurate automation

Hello again. This time I got the hang of the gif tool. look at the gif: I’m automating Dry/Wet knob. I set the point to be at 50%. I play the track, and it shows a different number on that knob every time i restart the pass. Question : why does it happen? is it some sort of “analogue-esq feel”, or just poor coding, or user error?

edit: so it seems that if i increase the the line length, then cubase has enough time to go to 50%, but if the slope of the line is steep, then it slows down for some reason…