Trash problem with Gmail

My wife and I both use Em Client with Gmail.  My wife finds that emails she sends end up in both her Sent and Trash folders and I am trying to find out why this is happening.   I should add that I have no such problem. 
I would be pleased to know if  I should be looking in Em Client or her Gmail account for the solution. Thanks.

I am not using GMail with IMAP, so haven’t personally experienced this, but I understand that sometimes it does happen that draft versions end up in Trash after the message has been sent.

Gary is absolutely correct.  by default, eM Client saves drafts every 3 minutes.  When the message is actually sent, the drafts will then be sent to the trash folder.