IMAP sync not working properly

Dear community,

I have an issue with IMAP sync on an web.de email account.

My Setup:

a) web.de mail adress

b) IOS 6.1.3 mail client IMAPed to a)

c) MacOS X 10.8.4 (latested patched installed as per today) also mail client IMAPed to a)

The issue:

When deleting or moving an email via the mail client, it actually gets deleted/moved accordingly, at least from the view of the client.

Now logging on to the wed.de portal, I can still see the mail (both deleted and moved) in the inbox - though the mails appear in a "read" status.

Though when doing the same via the portal - all get's reflected properly in both IMAP clients.

What has been done so far:

1. Remove and re-setup IMAP setups on the both clients.

2. web.de support not having an idea other than request me to again remove and re-setup IMAP clients.

Intresting to know:

my wife using the same Mac (same software versions) plus also an IOS 6.1.3 IMAPed mail client, also with an web.de - and sche is not having the same issue

Anybody having an idea?

Is this a client issue related setup or anything else or could it be something on server side?

Thanks

BH