A bit more detail now on why it was happening. Seem to remember that one was supposed to always have a hand on the thrust levers after the initial advisory. If I remember correctly, I think TOGA will only activate with flaps extended.
"The FAA is urging Boeing 777 operators to modify wiring to eliminate the risk of uncommanded throttle advances while aircraft are on the ground.
Boeing in 2015 issued a recommended fix for the issue, which has led to several in-service incidents.
“The majority of events occurred during taxi, and in one event the autothrottles advanced after landing before the speed brakes were retracted,” the FAA said in a non-mandatory special airworthiness information bulletin issued June 11. “Investigation revealed that these events were probably caused by a short between grounding wires to the [takeoff/go-around] switches. When this occurs, the aircraft senses the . . . switches have been pushed, the autothrottles activate in [thrust-reference] mode and the thrust levers advance to set takeoff thrust.”
The recommended repair is to change the grounding wires, the FAA said.
Boeing in March 2019 issued a flight-crew bulletin that explains how pilots can monitor thrust-lever movement and prevent uncommanded changes.
The issue is not severe enough to warrant a mandatory change via an airworthiness directive, the agency said."