We’ve discovered that for the native Android app, you must also apply a patch to the restws module. If you have access to your server, you’ll need to run these commands from the ssh or the terminal:
cd profiles/farm/modules/contrib/restws
wget https://www.drupal.org/files/issues/2020-07-28/3161965-2.patch
patch -p1 < 3161965-2.patch
This patch has been added to farmOS/farmOS@3b20638, and should be a part of the upcoming farmOS v1.5 release, but you will still need to apply the changes manually, with the commands above, even if you git pull.