IOS Photo Sync Question

Hi. I have a Seafile server setup on Ubuntu Server 18.04.01 running within virtual box. If all goes well I will setup a dedicated hardware machine for home use. It seems to run well so far but I have a question about the sync of photos from an iPhone. All my photos uploaded fine but then I tried deleting one on the iphone. This deletion was not synchronized to the Seafile server, even when I deleted it from the recently deleted folder on the phone. Is this as per design? It’s certainly different behavior to the desktop client that synchronizes the delete.

One other thing; I have not come across any documentation for the IOS client. Does anything exist?