cant get exif data python

I store my photos on Google Photos and they are in chronological order. When i download them to my MacBook the metadata is still present on all the photos and it records when the photo was taken etc. I have written a short Python script to extract the date the photo was taken. However, on some of the photo files the exif data is completely blank (even though it displays it on the photo info on the MacBook).

Any ideas why this is?

It only appears to be on about 5% of photos.

Why does it show on my MacBook but not on the exif dictionary is completely blank.

from PIL.ExifTags import TAGS
my_img = Image.open("one.jpg")

exif_data = my_img.getexif()
print(exif_data)

for tagId in exif_data:
    tag = TAGS.get(tagId, tagId)
    data = exif_data.get(tagId)

    print(f"{tag:16}: {data}")'''