[FIX] user_id changing to activity team leader by default

mail_activity_team/models/mail_activity.py

@@ -46,14 +46,13 @@ class MailActivity(models.Model):
         if not self.team_id:
             return res
         res['domain']['user_id'] = [('id', 'in', self.team_id.member_ids.ids)]
-        if self.team_id.user_id:
-            self.user_id = self.team_id.user_id
-        elif len(self.team_id.member_ids.ids) == 1:
-            self.user_id = self.team_id.member_ids
-        elif self.env.user.id in self.team_id.member_ids.ids:
-            self.user_id = self.env.user
-        else:
-            self.user_id = self.env['res.users']
+        if self.user_id not in self.team_id.member_ids:
+            if self.team_id.user_id:
+                self.user_id = self.team_id.user_id
+            elif len(self.team_id.member_ids) == 1:
+                self.user_id = self.team_id.member_ids
+            else:
+                self.user_id = self.env['res.users']
         return res
 
     @api.multi