Hello,
Intel motherboard dq87pg ignore/corrupt all UEFI BootXXXX/BootOrder variables except last one set.
So if you install Windows then Linux you've got in boot menu (F10) only Linux (grub) and if you installed Linux then Windows you've got only Windows Boot Manager by F10.
It appears to be worked well only in origin firmware ver. 0030, but in 0035,036 it was broken by ignoring UEFI variables. Also if you reflash the same motherboard (0035/0036) with both installed Win/Linux with origin 0030 firmware you've got all announced OSes in boot menu (F10) back(!). So it's just ignoring then and seen then only in ver. 0030
Version 014x corrupts previous set BootXXXX variables when you set new one. When you set new BootXXXX var via efibootmgr it's ok, but when you reboot and check it again with efibootmgr -v, you will see corrupted device path in all variables. So you've got again only one OS in boot menu (F10)
Also it's reproduces for all four motherboards in my hands