Creation date of photo/movie is changed upon opload from within iOS Photos app

If I upload a photo/movie from within the iOS Photos app by selecting it and exporting it to my Nextcloud, the creation date of the resulting file in the Nextcloud will be changed to the current date/time. This is annoying because the creation date of a photo/movie is very important.

Luckily, if I upload a photo/movie from within the iOS Nextcloud app by pressing on the “+” button, then selecting the photo/movie from the list does NOT change the creation date in the resulting file in the Nextcloud.

Is the behaviour from within the Photos app a bug or intended as a feature?