Switching between activities get lost focused window by making focused and not visible, but display another of the opened windows. Clicking on that window actually trigger an action on the "focus but nos visible" window, like if it was visible.
Even during this 'episode', is not possible to access any of the panel elements like Application launcher, systray.... it's like they're not there.

STEPS TO REPRODUCE
1. Switch to another activities.
2. Stay on that activity or switch back to previews one.
3. Try to switch to other window (with Alt + Tab or clicking on Task manager)

OBSERVED RESULT
The desired window get focused but isn't visible.

EXPECTED RESULT
The desired window get focus and is visible.

SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.25
KDE Plasma Version: 5.25.1
KDE Frameworks Version: 5.95.0
Qt Version: 5.15.5

ADDITIONAL INFORMATION
After some many attempts of Alt + Tab, the behavior disappears.
I note this since version 5.25.0.