i will have to look at mine but usually the other OS is for Win 7 or some other OS. It would have been set to use Secure Boot so the other OS option would seem to be out of place.
Maybe you could verify exactly where you are seeing the setting so I can verify on my system..
I just checked mine, and under the Secure Boot options it did say Other OS. I have changed mine to UEFI and it booted normally but I will keep an eye on it..
I have just built a new computer with the ASUS ROG Maximus Hero XII Z490 and installed the latest Windows 10 (2004 version) and I noticed that when going into my BIOS under the Boot menu, that it's currently set to 'Other OS'. Am I suppose to change this to 'Windows UEFI'?