Indeed the NIV's should be revoked/canceled if the IV's are approved.
My guess is that if the IV's are denied, the NIV's could be revoked as well, but, as per the following paragraph, in such case, you can argue the decision:
"FAM 403.11-4(A) (U) Visa Revocations by Consular Officers
(CT:VISA-1275; 05-10-2021)
(U) Although the decision to revoke a visa is a discretionary one, you should not use this authority arbitrarily. When practicable, you must:
(1) (U) Notify the individual of the intention to revoke the visa;
(2) (U) Allow the individual the opportunity to show why the visa should not be revoked; and
(3) (U) Request the individual to present the travel document in which the visa was issued"
Regarding all the grounds for revocation, you can read the following links (both are the source of the extracts I've shared):
https://www.law.cornell.edu/cfr/text/22/41.122#d
https://fam.state.gov/fam/09FAM/09FAM040311.html