@4am@lemm.ee already explained most of it, Bitlocker comes into play because the recovery environment can be booted without needing to provide the recovery key for Bitlocker, the vulnerability that is being patched additionally allows bypassing the need to log into it.
That said, Microsoft frequently disables Bitlocker anyway to do OS updates, it really only works if you enable the additional pin feature.
@4am@lemm.ee already explained most of it, Bitlocker comes into play because the recovery environment can be booted without needing to provide the recovery key for Bitlocker, the vulnerability that is being patched additionally allows bypassing the need to log into it.
That said, Microsoft frequently disables Bitlocker anyway to do OS updates, it really only works if you enable the additional pin feature.