Windows 11 - UEFI Bios

[kalpana]

I purchased a new computer. A Minisforum HX90G (Ryzen 9 5900HX & AMD 6600M GPU) I love this little computer...
It came pre-installed with Windows 11. And since I added a second SSD to the computer, I decided to go ahead and Dual-Boot Kubuntu 23.04
I figured I'd keep Windows 11 on one of the SSD's, just in case there was a game or something I wanted to play...

Well, the other day, Windows 11 did an update of it's own. Right after a reboot, it no longer booted from my Kubuntu drive... it went straight to the Windows Bootloader.
So, I went into the bios, and changed the default boot-loader back to Grub on my Kubuntu Drive. Rebooted, and the computer went into Grub, and I booted Kubuntu from there.

Turned off the computer that night... woke up the next moring, and booted the computer... Lo and Behold the Bios had reverted back to booting to the Windows 11 Drive by default!!!

I figured I may have forgotten to save the bios before I exited... tried it again...
Same thing the next day. Lather, rinse, repeat, for the last few days.

My Computer will no longer boot from the assigned drive in BIOS, it keeps reverting to the Windows Bootloader.

Does anyone know what causes this? Secureboot? TPM 2.0? Microsoft's nefarious attempt to rule all PC's?