IPad external monitor use and behavior

Using 11 inch M2 iPad Pro, Dell monitor and dock with a DP cable. I use stage manager with an external monitor and all is well until iPadOS 18.0.1, I have 2 different apps open, 1 on the iPad screen and 1 on the monitor. If I close the one on the iPad screen, the app on the external monitor moves over to the iPad screen. How do I get the external monitor to keep the app on it and not move over when the app on the iPad is closed?

I got it to work correctly for about 2 hours today, then back to app sliding over after all apps get closed in the iPad.

FYI: iPad Docks visible on both screens and stage manager active on both screens. Recent apps and docks are on both screens.