Yeah, fairly sure that's intentional, guy who is knocked down can't move, can't roll, but can block and attack. A bit silly though as the requirements for the knockdown nudge allow for a free hit 100% of the time, and the guy knocked down isn't stunned long enough for you to hit him before he can block.
It really should be changed. Being knocked down from a nudge is rare enough that you shouldn't be able to
attack while lying on the ground/getting up. If kicking someone is good enough to get a free hit, then a nudgeknockdown should be more than enough to get a free hit.
