Reasons why there would be no EXIF data at all on a received photo?

I received a photo and it’s critically important for me to be sure of its veracity.

The photo was received on my iphone via imessage. I downloaded an EXIF data app and imported the photo, and the app said there was no EXIF data available. This individual has sent me many other photos via imessage so I checked some of those – all of them had full and complete metadata available. I checked other photos sent by other people – they had metadata too. This one particular photo has none (just file size and image size).

Can someone please explain some other possibilities as to how this could happen OTHER than the individual purposefully wiping the metadata from the image?