I've tried three times to get that achievement, building 25, 29, and 27 hyperlanes, and have never been able to unlock it.  There was another thread on this forum talking about it and several others had failed to get it, while one person had.  I consider it bugged and have given up on it.

Sorry for the late response, though I did manage to get this to work via a post on steam.

What I did was save the game (for in case it didn't work), then go through every gate and disconnect them so not a single gate connected to another, then reconnected them all again after and the achievement popped. I hope this helps you guys as well.

i tried this yesterday. disconnected all my gates and reconnected them. didn’t work. then i unconnected them all again and daisy-chained them in series so that gate 1 connected to gate 2 connects to gate 3 etc. when i had 20 gates connected in sequence like this, the achievement popped. i think the achievement is for having 20 gates connected to 20 different gates, not for having 20 gate connections. there’s a subtle difference that’s misleading in the description of the achievement. 

I'll see if we can get the description tweaked.