can't empty trash-grayed out folders persist

Has anyone seen the following issue (v6.xxxx)?:

In Trash I have some just deleted emails along with 15 or so grayed out subfolders the contents of which were deleted long ago. Empty nested sub folders, or so it would seem. I empty the trash and it all goes away. But then one by one the grayed out folders reappear and within 2-3 min. they are all back. I can repeat this scenario as often as I want.

The reason this bugs me is because on downloading and opening new email I see long annoying delays. When I check on Operations I see that these seemingly deleted or grayed out folders are being synced, over and over, and there are or were many hundreds of emails in these folders. Why would anything in the  Trash be synced at all?

In going to Yahoo Help they say you can do cleanup of the Yahoo email server from our email client. Apparently not. I  just learned that our email sits on a Yahoo email server and not an ATT server. ATT is my internet provider. All ATT tech support will do is help with settings in the client (for $$$) or Yahoo webmail, so this is a Yahoo issue. I have not tried to call Yahoo yet.

Any suggestions?

I see the same thing in version 7.1.33101.0