Cannot delete a registration field in 6.6

Cannot delete registration fields.

When I upgrade to 6.6 I lost the ability to delete a registration field (General Setup – Registration)

You can see how phone is listed twice here

https://educatezambia.com/submit/

The first “phone number” that is required is from registration fields and should not be showing up there but is – however, when I go to delete it, it has disappeared.

I use this theme on several sites and noted to that this only happens when I upgrade – before then it works fine?

Any help would be apprecaited

Any help would be appreciated