Lightroom Classic version 14.4.1; macOS 15.2.
Open a catalog with images that have a shutter speed of 0.3 sec or longer; alternatively import such an image.
From Library Module activate the the Library Filter, click Metadata and change one of the columns to show the Shutter Speed. Select a value that's 0.3 or more. (I think any value that is not formatted as a fraction will show the bug.)
The matching images are displayed. Click one of them. In the Metadata panel the Shutter Speed value is blank, rather than showing the value from the Library Filter.