Well I checked under my taskbar and it do render it properly. My guess it is something else causing it.
I completely agree with Basj. Right now my system is Windows 10 22H2 (build 19045.3570) + WindowBlinds11 + Start10 + OldNewExplorer + ExplorerPatcher:
No any problems. Just interesting, do you see that issue with any other semitransparent skins or with BetterAeroVistaX only?
If "Yes", try to remember if you may have made any small changes to the Windows registry. If you haven't touched the registry, I'm afraid there's something wrong with your Graphics Driver...