The error/warning is caused because the versions numbers of the GPT and GPC components of the GPO don't match. The GPT version number is stored in the AD against the GPO object and the GPC version number is stored in the gpt.ini in the sysvol share.
Normally as you edit the policy these numbers are incremented and is used to confirm that the GPT and GPC are in sync. For some reason the version number on this policy don't match, hence the warning.
The easy way to fix this is, is to edit the policy again, by adding and removing a setting, this will cause the version numbers to be updated and should sync the GPT and GPC version numbers.
Gary.