Another problem with Automount (classic automountd or newer systemd) is that it does not provide a way to run mount unit as a non-root user or set any environment variables including PATH or HOME for mount programs.
When rclone is run normally, it will use HOME to derive location of cache and rclone.conf and perform tilde ~ expansion in some settings. It's not possible when rclone runs under Automount so user should at least explicitly submit --config and --cache-dir options as absolute paths.