Yep - once Windows Update detects that the device is missing the applicable security update, the update will be reinstalled during a subsequent update scan. There can be a delay before it comes back. Windows Update does not necessarily reinstall an uninstalled update immediately. The device may need to perform another scan, or you may need to select "Check for updates." If the update is still being offered, Windows will normally download and install it again.
There are also some exceptions. If Microsoft has superseded or expired the particular KB, if the KB is no longer applicable to the current Windows build, or if the update has been temporarily paused/blocked by Microsoft, Windows Update may install a newer cumulative update instead of the exact KB that was removed. In the case of Windows 11 cumulative security updates, this is common because a newer cumulative update generally replaces the previous one.
Also, uninstalling a cumulative update is usually temporary from a security perspective. If Windows Update remains enabled, you should expect the vulnerability fixes to return either through the same KB or, more commonly, through a newer cumulative update that contains those fixes.
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hth
Marcin