Maybe I hadn't noticed this earlier or at first because I normally have the taskbar & Sys Tray transparent.
Sure, interesting you are not seeing the same behaviour.
As I showed, 26052 doesn't do this.
Check the version of Edge Dev, Windows Copilot is still driven by EDGE. From what I see your Copilot is opened by EDGE DEV, perhaps your EDGE DEV is not the same Version as mine?
Also, I don't use transparency on my taskbar. You can see in my previous screen shots that it stays above the system tray in both Canary and Public Build. 😎😉
Same on 3 different machines with Build 22631.3085. 🤷♂️