Apple mail places sent itens in inbox

Hi,

Apple mail client, with my office365 email, is placing the emails i sent in my inbox (as i sent them to me) and also every 4 hours or so, marks all my emails in my inbox as unread.

Since i figured it might have been some issue or mistake i removed the account from the mac and reconfigured from scratch and it seemed to be ok for 3 ou 4 hours and it started again.

This does not happen with my yahoo account. Also in my iPhone (from where i haven't removed and reconfigured the account does not happen) and also not in the webmail.

I'm narrowing this to the mail client since i've made a test during a weekend where i didn't open the mail client and received and sent emails from the iphone and was smooth, once i opened the Mail client on my Mac Monday morning ... boom, hours later the mail was crazy again.

Did any one faced this before, it's driving me crazy!

Thanks for the help.