Since installing version 10 Beta, two copies of every incoming email message are shown in my Inbox. Deleting either message deletes the other copy also. I am guessing this is a result of the new “Inbox Categories” feature, which I have not enabled.
Needless to say, it is very annoying.
Btw, another user posted in Spanish on this forum essentially the same issue: Llevo mas de 2 semanas recibiendo los mensajes duplicados. Por favor ayuda, es muy molesto