Your code looks correct, so we can explore options related to your navmesh and/or how your drone is placed in the level.
But first, a quick question. If the player moves next to the drone, will the drone to the player?
The reason I ask is that if the drone is positioned too high from the floor of your level, it might not be able to move correctly with the navmesh that is generated in your level.
Ah, apologies, I misunderstood. Then the issue might be that the patrol points are too high off the ground. As this doesn’t allow the navmesh to give a proper path (it’s related to a setting called “step height”)