If you teleport in Vanish to a player, all their turrets will enage you, even if you are out of sight behind a wall they will try and shoot through it. 

I am using the Player Administraion plugin to teleport https://umod.org/plugins/player-administration
I am even running the Don't Target Me Plugin but they still enage upon teleporting.

Any ideas?

Read the documentation and plugin update notes:

"Added new command to toggle collision in vanish using /collider. Having the collider toggled off will mean you will trigger sensors and traps(land mines etc.) but it will allow you to "clip"  to objects such as cargo so you dont slide off. Toggling it back on will stop you from triggering traps and also stop you from receiving radiation."

I imagine you have the collider options set to off ?