Lighroom Classic Filter Doesn't Recognize Camera or Lens if Video

Manufacturers often do embed the camera and lens information in videos, but there are multiple metadata sections in which they can record them (Quicktime, XMP, Makernotes, EXIF of a JPEG sidecar).  There are industry standards governing Quicktime, XMP, and EXIF metadata, but no unifying standard that tells camera manufacturers which is preferred (as there is for photos). 

LR will read the fields from the XMP section of the video file and the EXIF section of a JPEG sidecar (if present).   It doesn't read them from the Quicktime section or the Makernotes.

For this video, Nikon has embedded the information the manufacturer-specific Makernotes:

[MakerNotes]    Make                            : NIKON CORPORATION
[MakerNotes]    Model                           : NIKON Z 7_2
[MakerNotes]    Lens Info                       : 100-400mm f/4.5-5.6
[MakerNotes]    Lens Make                       : NIKON
[MakerNotes]    Lens Model                      : NIKKOR Z 100-400mm f/4.5-5.6 VR S
[MakerNotes]    Lens Serial Number              : 20012567
[MakerNotes]    Lens Type                       : VR
[MakerNotes]    Lens                            : 100-400mm f/4.5-5.6
[MakerNotes]    Lens Data Version               : 0801
[MakerNotes]    Lens ID                         : Nikkor Z 100-400mm f/4.5-5.6 VR S

There's no technical reason why LR couldn't read the Makernotes metadata, in the same way that it reads proprietary raw files.  But Adobe has chosen not to expend the effort.