Thread/Sent Email issues/missing

There are a couple of issues coming through here..

1. When an email is sent from Zero to a non-Zero email (gmail in my testing) and then replied back, the thread is missing. The reply email isn’t visible in Zero.
2. Instead the inbox shows the original “sent” message but not the reply

3. Subsequent replies aren’t visible at all if you continue to send/reply to that same thread.
   
   
   https://www.loom.com/share/dba5b792e63347aa826842df25488923?sid=e486011f-c2ec-40e5-a0ee-c65dd94a3630