I did this route a couple of days ago and was awarded the badge on the first go-round. Maybe your spawn point was beyond the starting arch? Though it certainly looks as though you covered enough distance to have gotten the badge, presuming you selected it as your route at before starting.
Well, I’m glad someone achieved the Knickerbocker Badge.
Yeah I covered the route twice. I will again soon. In the mean time I will try the reverse route to see if I can claim the badge for Knickerbocker Reverse.
Just had the same issue with the Highline route (both selected the route at the outset and rode far longer than posted distance to accommodate any lead-in distance, etc.).