iPhone is showing blacklisted (Lost or Stolen via IMEI)

We recently came into an issue where a iPhone was reported lost/stolen to Verizon in August 2024, then was found and the original owner requested to have the device removed from the lost/stolen list (blacklist or negative list) in September 2024. The device became completely functional on Verizon (the carrier that issued the carrier blacklist), however other carriers such as T-Mobile, AT&T, etc where showing the device was still assessed on the Lost/Stolen list, making the device ineligible for activation.