Custom fields appear in wrong order when viewing in "View and Edit Custom Fields"

Created a set of custom fields in 4.4.6 and upgraded to 4.5 (beta 3) and viewed the custom fields (Administer -> Custom Data and Screens -> Custom fields, then View and Edit Custom Fields) and fields are listed in incorrect order, yet the "arrow icons" to reorder them are correct, ie the custom field that is first has just the "move down one row" and "move to bottom" icon, yet appears in the wrong place in the list of custom fields, ie not at the top. Likewise for the one that is supposed to be at the bottom.

Oddly, when the custom fields are previewed the form appears correctly, ie with the fields in the correct order.