cp -a into mounted ouisync repo partially fails

[Juul]

When running cp -a foo ~/ouisync/repo, where ~/ouisync/repo is a mounted ouisync repo, and foo is a directory with contents I get an empty foo directory inside ~/ouisync/repo which is then synced to other peers and I get the following error:

cp: setting permissions for '/home/<user>/ouisync/phone/foo': Operation not supported

To compare, using cp -a into a regular filesystem that doesn't support *nix permissions (FAT32) results in a successful recursive copy with the following output:

cp -a foo /mnt/tmp/
cp: failed to preserve ownership for '/mnt/tmp/foo/bar/baz': Operation not permitted
cp: failed to preserve ownership for '/mnt/tmp/foo/bar': Operation not permitted
cp: failed to preserve ownership for '/mnt/tmp/foo': Operation not permitted

This is what I would expect from ouisync. It is not unusual for programs, gui or otherwise, to default to preserving permissions on copy so this effectively stops some programs from copying data into a ouisync mount.