Pretty sure it is not lag but a realism feature.
Tanks that are teleporting like that aren't tanks you've spotted yourself, but scouted by others. And just like in real life if you were communicating by radio, you'd know kinda where the other tanks is if he's 300m away on the other side of some bushes, but you'd really be guessing. It's neat and doesn't allow teams to just turtle back and have perfect sniping opportunities across the map. Also teleporting decreases and you're able to see them for longer periods at further distances as your tank improves and you improve your radio. I think that's why its an upgradeable feature at all. Sure doesn't improve Vox, lol. Also enemy tanks stop teleporting when they are in your tank crews visual range which you can increase by buying modifiers for your tanks.
