This can happen because EXIF/XMP metadata is not guaranteed to remain unchanged once a photo is copied, synced, edited, or converted.

A copied file may no longer be the original camera file. Transfer software, cloud services, phone backup/restore tools, image editors, and sharing sites can rewrite metadata fields such as device, software, or processing history. On Apple workflows, syncing through iCloud or iTunes, or restoring onto a newer phone, can result in metadata reflecting the later device/software environment rather than the original capture source.

Format conversion can also do it. For example, converting HEIC to JPEG during transfer may create a new file and write new metadata while preserving the original capture date.

So the likely explanation is: the image you checked was a derivative copy, not the untouched original, and some step in the workflow rewrote parts of the metadata. If provenance matters, inspect the original file straight from the capturing device or its first storage location, not a transferred or converted copy.