Hi Nam,
I am Sumit here to assist you with this question.
Yes, that is a bug in Windows 11. The easiest fix is, not to hover over the search icon, or restart the explorer process using the steps below:
Press Ctrl + Shift + Esc to open Task Manager. You may need to select More details at the bottom of the window to see everything.
Select the Processes tab.
Scroll down to Windows Explorer, select it, then select Restart.
The process may take a few seconds, and your taskbar and Start menu may not be visible while Windows Explorer restarts. You can close Task Manager when the process is complete.