About your Windows 8+ report, yes, what you describe is perfectly normal, what many people tend to forget is that UEFI does not necessarily means GPT, a UEFI can access "MBR style disks" just fine (the opposite, BIOS acccessing a GPT disk needs special provisions, so-called hybrid MBR's and "special" code in them).
You evidenced however yet another aspect of more recent NT Windows booting, until XP NTLDR was both the boot manager and the OS loader, now BOOTMGR (and bootmgr.efi) is just the boot manager and it chainloads a separate OS loader, the WINLOAD.EXE (or winload.efi).
https://msfn.org/board/
and:
http://reboot.pro/
(on this latter under the nick of Wonko the Sane)
About your Windows 8+ report, yes, what you describe is perfectly normal, what many people tend to forget is that UEFI does not necessarily means GPT, a UEFI can access "MBR style disks" just fine (the opposite, BIOS acccessing a GPT disk needs special provisions, so-called hybrid MBR's and "special" code in them).
You evidenced however yet another aspect of more recent NT Windows booting, until XP NTLDR was both the boot manager and the OS loader, now BOOTMGR (and bootmgr.efi) is just the boot manager and it chainloads a separate OS loader, the WINLOAD.EXE (or winload.efi).