This is disappointing. My overlay CPU UTIL is also way off (50%?), so that it's basically useless. This happens to be a fresh, days old install of Windows 11 (build 22621), and latest AMD Software (23.9.1).
It seems AMD needs to modify some behaviors of the overlay, but they have not yet. There may have been some changes to Windows in 2022 if reports are correct (like this, also explains a workaround if desperate). Other apps can obviously read the value fine (AIDA, HWINFO), so AMD should be able to fix this... eventually. (I just noticed that my fresh install fixed a few things, like unnecessary "CUR" in temp, overlay toggles, so that's nice.)