Does it also occur if you are in sport mode?
Never use Sport Mode, seems plenty adequate power wise in normal mode. I might when going down a steep hill if could get it into a lower gear for brakeing, but not sure it would not shift up cause Sport Mode is also AUTO or Manual +/- Shifting).
Watched it again yesterday (July1) when on the same route and felt it I think in the same area of the road (would be the same time in to the trip, slight up hill, running about 40 or so MPH - EV Light was off, so Gas Engine was running). It is noticeable but not extreme.
I noticed it other times also - think it was even on a slight downhill slope. Might have been EV Mode then (not sure).
My first thoughts were it is when Gas Engine is running (maybe a misfire like the one the guy that had it so bad that he got a new car and some other benefits from KIA when they could not fix his car).
Anyway, there is something about these cars that is not 100%. KIA apparently standing behind the product.
That Said, I still like mine and it (whatever to cal it) is not severe, but you notice it (Maybe getting worse). I mis-quoted miles on car (it is around 5200 not over 5500).