Thanks for mentioning Secureboot, I was able to fix the problem.
During installation of 18.04, I selected the option to enable Secureboot, and it enabled "Windows" as the secureboot OS in the BIOS. After I went back into the BOIS config and changed the Secureboot OS to "Other", I was presented with teh dialog to enter the key at boot, and once I did that everything worked.
Thanks for mentioning Secureboot, I was able to fix the problem.
During installation of 18.04, I selected the option to enable Secureboot, and it enabled "Windows" as the secureboot OS in the BIOS. After I went back into the BOIS config and changed the Secureboot OS to "Other", I was presented with teh dialog to enter the key at boot, and once I did that everything worked.