I noticed my AI allie sends it's envoys to planets I used to have, if I give him a quest to send a envoy to one of my planets he sends one to it to get the job done and sends it away to one of hte other planets I stripped.
Coud just be whit stripping planets but I noticedm y enemies sending envoys to me as wel from time to time, makes it imposabel to get pacts when your playing whit AI.
