This is a regression. Tested in //UE5/Release-5.0 CL20979098
Preview Mesh does not disappear after releasing the Keyboard Shortcut as expected. The Mesh remains until the editor is restarted or another menu is opened as a tab like the Editor Preference.
The preview mesh disappears.
The preview mesh remains and will continue to appear under the mouse.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-169712 in the post.