Is Perpetual dropdown not populated in Agreement create/edit form (MG back port)

Overview:

When you create or edit a new agreement the Is Perpetual dropdown should offer options Yes or No. Instead no options are shown
Steps to Reproduce:

1. Start to create new agreement
2. Click on the dropdown for 'Is Perpetual'

Expected Results:

Yes/No
Actual Results:

No options
Additional Information:

The dropdown should be using the Global.Yes_No refdata category

However the fetch we do for refdata for the form is:

/erm/refdata?filters=desc==SubscriptionAgreement.AgreementStatus%7C%7Cdesc==SubscriptionAgreement.ReasonForClosure%7C%7Cdesc==LicenseAmendmentStatus.Status%7C%7Cdesc==InternalContact.Role%7C%7Cdesc==DocumentAttachment.AtType%7C%7Cdesc==SubscriptionAgreement.IsPerpetual%7C%7Cdesc==RemoteLicenseLink.Status%7C%7Cdesc==SubscriptionAgreementOrg.Role%7C%7Cdesc==SubscriptionAgreement.RenewalPriority%7C%7Cdesc==AgreementRelationship.Type&sort=desc;asc&max=100

Note that this includes 

desc==SubscriptionAgreement.IsPerpetual

This is incorrect as we use Global.Yes_No for this field