Jekyll incremental build/serve and watch command (like the one used by ./tool/serve.sh) will report this error: ERROR: directory is already being watched.

Unless you're editing files under site-shared, you can safely ignore the error. If you are editing files under site-shared, you might not see updates unless you restart the Jekyll command.

Preliminary investigation suggests that an appropriate plugin tweak and/or extension should allow us to eliminate this error message.