Hmm there might be a chance i goofed when i installed it as you said. might gone with the default first time and for some odd reason pressed Grub this second time. since i have had this problem with other Distros that came with Grub.
well i guess i just reinstall EndOS again before i get to comfy and see if it fixes it. or just live with going the bios route.
only as additional info:
Some Firmware / Bios has two places where you can set CSM legacy on/off !
In case it can be there is an extra setting for USB boot and system boot /drives… so you can set USB boot to have legacy option also system boot is uefi…