Globe prepaid roaming on 4G in the USA

I came here in the US on June 2022 with my Globe Postpaid. Roaming worked consistently fine; My phone's Cellular Voice & Data were set to LTE and has been connected to T-Mobile.

Fast forward to January 2023, my postpaid contract expired. I had my sibling in Philippines go to a Globe store on my behalf to request for "Porting" (changing my account from postpaid to prepaid). A store agent assisted my sibling, though the agent gave a disclaimer; The agent previously did the same thing (change a postpaid account to prepaid of someone in the US) and the user lost their roaming signal afterwards. I told my sibling to go ahead with it. The transaction was completed and we were told that it will take 24 hours for the changes to take effect. Over the next 24 hours, my Globe line was still connected to T-Mobile. Then afterwards, line went off and network indicator became "SOS only". I fiddled on my phone's Cellular settings including roaming, network selection, and cellular voice & data connection mode. My phone's signal went back when I switched the connection mode to 3G. It still connects to T-Mobile.

A side note - I also have a Smart line which was also a postpaid line ported to prepaid when I came here. It is set to LTE and connects to AT&T. So it baffles me that Globe prepaid only works with 3G when 3G is supposed to be already decommissioned here in the US.

Knowing that there's low chance of figuring this out (why prepaid line cannot roam on LTE while postpaid can) thru Globe's customer support channels, I decided to be at peace with it. What matters is that my line can still receive SMS for Philippine transactions where the number is enrolled at.

For short-term travelers who need LTE/5G mobile data access, it’s best to get a local prepaid SIM like T-Mobile’s.