To confirm, you received the SMS and checked the list of blocked numbers and didn't find it listed. Are you saying that the number had been in the list and suddenly was not?
I believe Erik is away for a few days but I'm sure he will read your response on his return.
I note that you asked the question:
"So, is it the game or is it the prefix?"
Given that NMS did not block the SMS when you had the prefix and it did block it when you did not, I suspect that it was the prefix. Also the "unlock" command is known to only work if you leave out the international dialing code, suggesting that NMS may not like such prefixes.
So while you wait for Erik to return and check if anyone has found anything to the contrary I suggest that you leave off the international dialing code and play your game whenever you wish. If the unwanted SMS still gets through then let Erik know and he will have more to work on. But hopefully you will not be bothered again.
I'll double check on whether or not the SMS/Call blocking feature support country codes or not. As to the original post, I don't think the game has anything to do with what happened.
I’m currently in Taiwan, and am roaming here. However, without the country prefix in the block list, I still received another sms that should be blocked. Is roaming not supported?
Have you updated to the non-Beta build or are you still on the Beta? There were some changes checked in to the non-Beta version that better support international numbers.
The team would like to dig into this further. If you could do the following when you see this happen:
As soon as you see an SMS/Call that should have been blocked, open NMS and choose "report a problem". After you do that, send me a private message and I'll ask for some information about your device that I can pass along to the team.