Why I can not upgrade to IOS 15, but only to IOS 15.1 beta

I registered as beta tester in March, and the last time I upgrade in 14th Sept is IOS 15 RC version. When the public version of IOS 15 released in 21th Sept, I tried to upgrade. But I can not get upgrading information.

And in 23rd Sept I received the upgrading information of IOS 15.1 beta version.

Is it because of being beta tester that I can only receive the Beta version upgrading information?