Maintaining original date when exporting Photos uploaded to iCloud from another device
When I try to export photos from the Photos app on my Mac, and use the "Export Unmodified Original for _ photos" option, the file dates (date created/date modified) of photos taken on an iPhone are not the original dates, but (I think) the dates when the photos were uploaded to iCloud from the iPhone. Exports of photos taken on (Fuji/Nikon) cameras and imported into the Photos app on the Mac are fine and show the original date.
Similarly, if I go to the Photos app on my iPhone, and try to export photos (e.g. by using Airdrop), the same thing happens, but in reverse. For photos taken with a camera and uploaded to iCloud, the file date is the date of upload to iCloud, not the original date, while export files of photos taken on the iPhone show the original date.
Has anyone come across this issue? Is there a fix i.e. when exporting a file, to get the original date of the photo rather than when it was uploaded to iCloud?
I am running Photos 6.0 on MacOS 11.6, and have selected 'Download Originals to this Mac'. I am running iOS 15.0.1 and have selected 'Optimise iPhone Storage' and 'Automatic' for Transfer to Mac.