Force a default lock screen GPO not working with Windows 10 LTSC 2019?

Hi guys

We have windows 10 PC with enterprise license. We are planning to upgrade from LTSC 2016 is an Enterprise build to LTSC 2019 is an Enterprise build. I have a GPO policy that sets a default lock screen/ login background. It has been working great with LSTB 2016 (1607) but stopped working once we started using Windows 10 LTSC 2019, which is based on the 1809 feature set. Instead of the specified background, it just shows a solid color.

The policies in the new ADMX’s look the same as our current ones, which we updated around the time that Server 2016 came up.

Well, it appears that the background just takes a while to appear, around 3-4 minutes. This is still pretty odd, considering it instantly shows up on other Windows 10 builds. It isn’t happening over time, but because I’m hitting Ctrl+Alt+Delete. Once it times out and goes back to the lock screen, the background shows.