This is a problem that has occured on two sites now, and its driving me scatty

I have a very simple site running the latest build of Easy Profile (though it has been around since 1.6?). There is only one enforced fields (required) (not including the ones I cant alter, such as name)

Primary Contact Number

I am trying to use 'force users to complete profiles' and people who HAVE the contact number filled out are being asked to complete their profiles.. which they have, when they save the profile they get the message 'Profile saved' followed by 'You must complete the required fields' of which there are none

If I turn OFF 'force profile completion' people can open up their profile and save it with no problem (as expected)

So the issue is somehow tied to the enforcement process which I really need to use but cant.

I had this on another site, but upgrading to the latest version seemed to work.