I’ve tried to alter the exif values and same issue…
exiftool -verbose -ExifIFD:FNumber=11 -ExifIFD:ApertureValue=11 -ExifIFD:FocalLength=24 -Canon:MaxFocalLength=24 -Canon:MinFocalLength=24 -ExifIFD:LensInfo="24mm f/2.8" -ExifIFD:LensModel="Canon FDn 24mm f/2.8"
which tags are you reading from?