Second hand information from a friend who was pax on board the flight that may have inspired this NOTAM.
Apparently the normal A380 tug was unserviceable and a lighter one was used instead. When connected to the aircraft on stand the aircraft started its engines as normal but the tug was not able to withstand the thrust.
The tug lifted up on the towbar causing slight damage to the aircraft nosewheel.
The delay was significant and my friend was not impressed, missing her connection and a whole day of meetings.
I guess when the normal tug is back in service the NOTAM may be withdrawn (?)