@mannikon I asked Phil Harvey, the author of ExifTool, how ExifTool comes up with the composite Lens ID, and he kindly explained, and wrote:
To properly set this lens requires two separate ExifTool commands:
- exiftool -lensmount=E-mount FILE
- exiftool -lenstype2=32819 FILE
The value of the LensMount tag affects how LensType2 is interpreted, so it must be written first.