When trying to access the Documents tab, I get "Item 12 does not exists" - no
such item errors.

This was after an upgrade to 5.0.1 - I used to get similar errors in 4.x series
and this has never worked properly...

Code:
2008-01-28 12:23:36,236 INFO  [btpool0-2]
[name=xx@yyy.org;mid=6;ip=41.245.141.11;ua=ZimbraWebClient - FF2.0
(Linux)/5.0.1_GA_1902.RHEL5_64;] SoapEngine - handler exception
com.zimbra.cs.mailbox.MailServiceException$NoSuchItemException: no such item: 12
Code:mail.NO_SUCH_ITEM Arg:(itemId, IID, "12")
        at
com.zimbra.cs.mailbox.MailServiceException.NO_SUCH_ITEM(MailServiceException.java:150)
        at com.zimbra.cs.mailbox.MailItem.noSuchItem(MailItem.java:1136)
        at com.zimbra.cs.db.DbMailItem.getById(DbMailItem.java:1728)
        at com.zimbra.cs.mailbox.MailItem.getById(MailItem.java:1069)
        at com.zimbra.cs.mailbox.Mailbox.getItemById(Mailbox.java:1856)
        at com.zimbra.cs.mailbox.Mailbox.getItemById(Mailbox.java:1825)
        at com.zimbra.cs.service.mail.GetItem.getItemById(GetItem.java:83)
        at com.zimbra.cs.service.mail.GetItem.handle(GetItem.java:61)
        at com.zimbra.soap.SoapEngine.dispatchRequest(SoapEngine.java:342)
This occurs multiple times in the logs if I just click on the documents tab...

I logged this as bug 24042 but figured the forums may be a better place to sort it out.
I'm very happy diving into the LDAP or mysql databases if someone can tell me what to look for...