On my first flight, after take-off I selected "retract" and noticed that one gear made an effort to retract and the other did not. I landed, turned the craft off, removed the camera then booted back on and inverted the craft, then selected "retract" ; at first the movement was the same so I put the switch back to "extend'. On the second try; I held a little pressure, (on the gear that had made no movement) towards the "extend" and locked position, then flipped the switch and simultaneously let go - and the gear retracted.
I believe setting in the box on a shelve after shipping from the factory, the screw gear got a little "set" to it. Flying RC taught us to always cycle the retracts prior to the day's first flight, as even the pneumatic retracts in RC would sometimes get a "set" to them. I've seen many flights where after take-off, pilots would fly around with a gear down until after landing and then find the gear would work after getting a little help. Maybe this is true of the H, my gear has performed flawlessly on subsequent flights, and "gear-up" check is now part of my pre-flight checklist.
