Lock in color/grayscale setting

I am running Ubuntu 24.04 on a Dell All-In-One.
When I open an impress file there is no color. I go to View->Color/Grayscale which has no selection. I select Color and everything is fine - until I close the file and reopen it later, when the Color selection is gone. I created a custom template with Color selected, but that didn’t help. How can I lock in the Color selection? I save these files in .pptx format.

try rather .odp

or add a report to this Bug List

Saving in .odp doesn’t help - the file still has color/grayscale selection blank. This problem is common across all of LibreOffice, not just Impress.