Pathfinder 2e – Monk Mountain Stance and Trip

This is a GM call

Each GM will have to rule what constitutes touching the ground…

But probably not

Trip leaves you prone on the ground. Touching the ground should generally be any time you’re not flying… and probably not jumping, swimming, climbing, etc.

While it’s technically true that you probably leave the ground momentarily when you’re tripped, you also technically leave the ground when you move quickly such as running. In these cases it is probably not a good call to have that count as ‘not touching the ground’ for the minute amount of time that it accounts for. There are plenty of other effects that may or may not accomplish this, but I see no reason to add that power to Trip.