Weird Email disappearing issues

[TheBundo]

Every so often, everything I have received since 8/18 disappears, and re-downloads the next time I check my Yahoo Email. I have no idea where it went. It just diappears from the Inbox. Everything I've Sent since that date has disappeared too, from the sent folder. Strangely, Drafts I have deleted reappear (and neither the Drafts nor the Sent emails are on Yahoo), and show as unread.

Sometimes emails remain, but return to the "Unread" state.

Does anyone have any idea what may be causing this? The loss of the "Sent" emails bother me most, since the Inbox is still on Yahoo and it re-downloads anyway (still that's a laborious download, and getting longer all the time). I think the missing Sent emails must be on the unit somewhere, but this problem has me pulling my hair out.

Again, Sent files which are local to the Mogul disappear, and local deleted Drafts reappear, and Inbox disappears too, all from about 8/18