Edit page theme options revert to default upon return

Hi,

since updating wordpress to the latest version when i ‘update’ any page after editing, all of my theme options for that page revert back to their default settings

however if i ‘view post’ my settings have been incorporated into that page but if i try to make any further changes and press ‘update’ again then they are no longer incorporated

I have tried activating different themes and they are all doing the same so i presume it is a problem with wordpress?

any help would be greatly appreciated

thanks

John