Black screen during boot

I have installed SLED15SP3 on an HP Z4G4 workstation and all is good about from a small issue when booting. I see the GRUB menu screen and proceed to boot but then the screen is blank until the login box appears. Normally this would not be a problem, but I have an XFS encrypted disk in the system and I do not see the prompt to enter the encryption password. If I press Escape, I see the text boot messages and also the prompt for the password. If I just type the password without pressing Escape, that also works but it would be nice to see the prompt as I do on other machines.

Does anyone have any advice?