Windows File System Classification stops working

First off, I accept this may be the wrong place for this but I have been very impressed with the file system knowledge in this forum and I hope if you dont know the answer you might point me in the right direction!

Basically I have a Central Access Policy, that CAP is applied to a Group Policy and on our file share we have the CAP set against a root directory. Within that directory we have folders which are classified with identifiers and our LDAP users are classified corresponding identifiers. We then have a rule in that CAP that says user allowed access if their ID matches the folder classification value.

This works… to a point, every now and then something goes wrong and the user is denied access… If you go into the settings as that user and view effective access it shows that the user is still green and should have access yet without removing the CAP you cant access the folder. The only way to fix it is to delete the Central Access Policy and Rule and re-create them.

Event viewer logs show nothing, has anyone any ideas whats happening here?

Thanks