diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index 6ca54653d87..bea8b37b867 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -2862,7 +2862,7 @@ class MailThread(models.AbstractModel):
             res = self.env['mail.followers']._get_subscription_data(doc_data, None, None, include_pshare=True)
             for fid, rid, pid, cid, subtype_ids, pshare in res:
                 sids = [parent[sid] for sid in subtype_ids if parent.get(sid)]
-                sids += [sid for sid in subtype_ids if sid not in parent and sid in def_ids]
+                sids += [sid for sid in subtype_ids if sid not in parent and sid in def_ids or sid in int_ids]
                 if pid:
                     new_partners[pid] = (set(sids) & set(all_ids)) - set(int_ids) if pshare else set(sids) & set(all_ids)
                 if cid: