Those who have purchased a Galaxy S24, Galaxy S24+, Galaxy S24 Ultra, and some other recent Samsung phones from T-Mobile have discovered that they can get rid of the network lock on their phones earlier than they're supposed to.
Carrier-locked smartphones in the US are restricted to the carrier they were purchased from to avoid fraud and prevent subscribers from switching to another carrier before completing the contract with the original carrier or paying off the device completely.
T-Mobile units cannot be unlocked before the device is paid off
T-Mobile officially has the same requirement for its customers (in addition to requiring the device be used on its network for at least 40 days), but for some reason, owners of the Galaxy S24, Galaxy S23, and some Galaxy Z Fold and Galaxy Z Flip smartphones can unlock their devices right away.
Trying to unlock the device from its Settings » Connections » More connection settings » Network unlock menu is reportedly going through without a hitch for many users, suggesting there is a bug that T-Mobile is either unaware of or has not officially acknowledged yet.
It could also be a change to the rules that T-Mobile hasn't made announced yet. Since 2021, Verizon has been automatically unlocking devices on its network after 60 days as it was one of the conditions set forth in its acqusition of prepaid carrier TracFone, and some are speculating T-Mobile is following in Verizon's footsteps after its purchase of virtual carrier Mint Mobile.
We'll let you know once we learn more about the situation, but until then, it's best to avoid using the unlock feature if you're a T-Mobile subscriber.