There is no server setting for a delayed turn off of antiwarp. There is just the ability to disable it when someone enters safe in the server.ini but no delay.
The bots can't just turn your antiwarp off, but they can unprize and reprize it to give the effect that they did, but you would have seen that.
This is either an undocumented client side bug/feature, or the previous line is true and you didn't notice.
Edit: Tested this and after ~2.5mins the bot(s) removed my anti and re-added it. I say bot(s) as it was unprized, prized, unprized, and prized again.
The bots can't just turn your antiwarp off, but they can unprize and reprize it to give the effect that they did, but you would have seen that.
This is either an undocumented client side bug/feature, or the previous line is true and you didn't notice.
Edit: Tested this and after ~2.5mins the bot(s) removed my anti and re-added it. I say bot(s) as it was unprized, prized, unprized, and prized again.