No, not normal, it's never happened to me.
My first thought was that cable tension might cause it to not engage, I'd check they were not too tight.
Then I might try and replicate it on the workstand, or upside down if no stand available. If I could get it to repeat - I'd remove the cable box and see if it engaged with a spanner - That narrows down the problem as being shifter or hub. A shifter problem is something you can probably diagnose and maybe fix yourself, anything within the hub would be a job for the professionals.
If you can't get it to repeat, I'd probably still disengage the cable box and check the smooth running of the cable and gear changes independently.
I have had a hub start skipping gears, though it's just been a single gear momentarily after a change, the issue was the pawl springs had become weak, a cheap and easy fix. That was after about 12 years of daily use, I doubt it's the case with yours.
Welcome to the forum, lets see and hear more about your bike!