There have not been any significant protests / disruptions blocking the airport access road in recent weeks, although the AEX has been disrupted a few times as a precaution.
I would offer the opinion that if you are having a daytime layover, and are able to get out of the airport via AEX without trouble, it's highly likely you can take the AEX back as well during day time. And even if not, highly likely that bus / taxi will get you back just fine -- I would just suggest positioning yourself on the Kowloon side at the end of your journey in case that is a concern.
I beg to differ as the Kowloon station on the AEx has bee closed many times, especially in the evenings where Hong Kong station has remained open.