Overclock in RPI UEFI ignored by Win 10

I’ve followed the usual instructions to overclock when using 64 bit Raspberry OS.
This works well and the “watch” command shows cpu speed varying between 600 MHz and 2 GHz.
However, when I increase the default in the Win 10 UEFI from 1.5 GHz to 2 GHz, there is no increase reflected in Task Manager.
I’m clearly missing something…?
Thank you in advance to anyone who can shed light on my dilemma.
PS In all other respects Win 10 is working well.

Sounds like an issue that should be reported on the UEFI github page