I know we discussed via chat, but noting here for consistency that I experienced the same issues using the web version of the mobile editor.
I pushed an update to the mobile editor today, can you try? I realised on iOS, you might need to delete the app and reinstall to clear the cache and load the new update.
I deleted and reinstalled the app, but same experience, unfortunately. Blinking “loading” for a couple of minutes, and then nothing saves.