Deleting photos from iPhone library also removes from Immich

Hello everyone! My wife is having an issue on her iPhone where deleting an uploaded photo or video from her phone storage also makes it disappear from her Immich timeline on her phone. Strangely, the file is still visible via a desktop signed into Immich. This has understandably made her concerned about losing photos if she deletes them from her phone and she is now running out of storage space.