iOS Nextcloud App doubles the used memory

Use Nextcloud for several months. Currently the beta because I thought that the solution is in version 17. But it is not like that.

Why are the images being uploaded immediately downloaded again? This doubles the memory consumption on the smartphone. 1x in the normal photo app and 1x in the Nextcloud app. Manually clearing cache helps temporarily, but I can not imagine that this is the optimal solution.

Did I set something wrong or is this a bug in the app?