This is not a bug. UAV is still connected to the UAV Terminal. Connection isn't terminated by death of UAV Operator. Anyone can take UAV Terminal from inventory of that killed unit and control linked quadrotor or diconnect it.

Shouldn't other UAV operators be able to take control of vehicle from a uav terminal? Or are the UAV's bound to the device in the players inventory separately?

It's bound to the device in the player's inventory, and there appears to be no way to disconnect it even with scripting unless a script deletes the whole dead body or someone picks up the UAV terminal and either manually disconnects it or has a script remove the terminal from his living body (you can remove it from living players with scripting, but not from dead units).

I would have expected a better mechanic to be in place, or at least the associated scripting commands to exist, and the workarounds to not be broken.

same... every time a player was killed on my server the UAV was locked as if it was still linked to that specific terminal which remained on the corpse.

we use a UAV spawn script to avoid problems like this... one gets locked or destroyed we simply spawn another during the mission

It is not "as if". It really does stay connected. Try pick it up and see.

I tried removing it with a script, but assigned items get bugged when a unit is already dead and cannot be removed by script. Only working solution was to delete the dead body.

I believe you should be able to "pick up" the terminals from dead units by recent script fixes now.

EDIT: If it's still bugged please make a new ticket!

Mass-closing resolved issues not updated in 10 days.