Windows 10 keeps changing EFI to boot first

So previously, I noticed that after the most recent update to Windows 10, Windows basically changed the EFI so it could boot first. A NVRAM reset fixed it...until the next time I booted Windows 10. Then it happened again. Now I think Windows is actively re-writing the EFI so it always boots first. Given I don't use Windows 10 all the time, this is frustrating. It's obviously a Windows-side problem. Any ideas on how to fix this permanently? Thanks.