A United Boeing 787-9, registration N27958 performing freight flight UA-2770 from Tokyo Narita (Japan) to San Francisco,CA (USA) with 4 crew, was climbing out of Tokyo's Narita Airport when the crew stopped the climb at FL230 due to a problem with the left hand leading edge flaps. The aircraft returned to Narita Airport for a safe landing at a higher than normal speed about 90 minutes after departure.
The aircraft remained on the ground for about 21.5 hours, then departed again but needed to return a third time for the same reason, see also Incident: United B789 at Tokyo on Jul 3rd 2020, leading edge flaps trouble.
The aircraft had already returned earlier the day due to the same problem, see Incident: United B789 at Tokyo on Jul 2nd 2020, leading edge flaps trouble.