As in 12.0? It shouldn't need to be installed first. It sounds like maybe it was already downloaded to your device and that might be why you are seeing as the update that is being offered to you.
This is what I see as of this morning. I guess I could try directly updating through iTunes to see if that is different. I can also try manually installing the ipsw file of ios 12.1
It says iOS 12.0 by mistake. It should say iOS 12.1 and the system will update to 12.1 It is a known typo bug actually if you read the first post of that iOS 12.1 bugs and fixes thread.
It says iOS 12.0 by mistake. It should say iOS 12.1 and the system will update to 12.1 It is a known typo bug actually if you read the first post of that iOS 12.1 bugs and fixes thread.