I've got a weird thing happening with my U Home 5G.

I use this sim card as a second sim on my S24 Ultra. I've used it ever since I got my phone which was last month. For the past 2 weeks, I've realised whenever it connects to 5G network I'll subsequently lose all mobile data. It won't even reconnect to 4G. This can only be rectified if I cycle airplane mode. After that same thing happens. As soon as I get a 5G signal, I lose all mobile data signal again.

Initially I thought this could be my phone problem as it was updated recently. But I've tried with another Umobile and YES sim card and there wasn't this problem at all. It held on to 5G for as long as I had the card in there.

I even went to the extent of getting the U Home 5G sim replaced. But the problem persisted. I even asked CS about it and they kept saying it's my phone problem. But I've tried other sims and this didn't happen to those cards.

Anyone has any clue what's going on/fixes?

How do I check if it's locked? Why would they even lock it when all I need from this plan is data for my phone?

I tried on my old iPhone 11 but the phone doesn't have 5G. With 4G signal there's no issue at all. Only when it establishes on 5G that's when the problem comes. Now I need to disable 5G in order for me to use this sim card on my Samsung.