Disappearing Custom Groups

We are running Openfire 3.6.4 on a Suse 10 server. End users are using the 2.5.8 Spark client. They will create a custom group and use the COPY TO function to add a contact from an AD group to the custom group. If the user then logs out and back in the group is gone and they have to recreate it. When we ran an older version of Openfire on Win2003 we never experienced this issue. Another caveat, sometime a group will save but only have a few contacts within it and not all of the ones that were added. Any ideas?