MY20.5 Range Rover Evoque (L551) First Edition P250 in Nolita Grey on a 70 plate
If you jump to 28 minutes 49 seconds in (on the above video), you'll see some further demonstration of similar troubles with the gesture feature on the new Evoque.
I think there may be a 'knack' to getting it right every time, but not sure as I don't have it on my own car (although I do have the remote tailgate lift).
Shame its not so good on the Evoque - my previous Peugeot 3008 had a gesture tailgate and it worked first time, every time. Very handy when carrying shopping.