I was on UA 935 LHR-LAX today. (787-9 #3954). Before pushback the pilot announced that due to a “maintenance issue”, the landing gear would be left down until 10 minutes after takeoff and we would notice a little extra noise.

After pushback it seemed to take two tries to start the second engine. Not sure if that’s related to the maintenance issue. And sure enough there was extra noise after takeoff until the landing gear was clearly heard retracting about 10 minutes in.

Any idea what this issue might have been?
Did the earlier LAX-LHR flight (same aircraft) have the same issue?