The code responsible for making sure the bot responds to you after it zones with you is this one little code block:
Code:
if(g->GetLeader())
activeBot->SetFollowID(g->GetLeader()->GetID());
If the bot doesn't follow you or respond to you after it zones with you, then carefully review your group_id and group_leaders tables and make sure the records match up and that you have all the required SQL updates for these tables.
I hope this helps you.