Hello,
This could be a known issue:
Disappearance of Windows 11 Taskbar Icons after Switching Virtual - Microsoft Community
Icons in taskbar went transparent after switching virtual desktops - Microsoft Community
Temporarily disable taskbar animations to see if that resolves the issue.
If you have Windows 11 installed, you can access the Feedback Hub by searching for it in the Start menu. Within the app, search for relevant keywords to see if other users have submitted feedback about the taskbar icons disappearing when switching desktops. You can also submit your own feedback to raise awareness of the issue. This can help Microsoft prioritize fixing the problem.
If the problem is indeed a known issue, Microsoft should eventually release a patch or update to resolve it. Keep your Windows 11 installation up-to-date by checking for updates regularly via Settings > Windows Update.
Regards,
Karlie