I recently upgraded to the latest version 7.5.2 and if i add a new property to a member it is not being applied properly to existing members. If i add a new member it works fine, but all existing members give an error (shown below) anytime i try to update one of their property values.

>  An error occured
> 
> The given key was not present in the dictionary.
System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at Umbraco.Core.Persistence.Repositories.MemberRepository.PersistUpdated

    Item(IMember entity)
       at Umbraco.Core.Cache.DefaultRepositoryCachePolicy`2.CreateOrUpdate(TEntity entity, Action`1 persistMethod)
       at Umbraco.Core.Persistence.Repositories.RepositoryBase`2.PersistUpdatedItem(IEntity entity)
       at Umbraco.Core.Persistence.UnitOfWork.PetaPocoUnitOfWork.Commit(Action`1 transactionCompleting)
       at Umbraco.Core.Services.MemberService.Save(IMember entity, Boolean raiseEvents)
       at Umbraco.Web.Editors.MemberController.PostSave(MemberSave contentItem)
       at lambda_method(Closure , Object , Object[] )
       at 

I'm not sure if this has anything to do with the upgrade or not, but any help resolving this issue and its cause woud be appreciated.