All the reporting on this I have seen including the schengenvisainfo article all point to a single Reuters article which can be found here:
https://www.reuters.com/world/eu-mov...ts-2021-08-27/ . This Reuters article implies this will not impact the vaccinated:
BRUSSELS, Aug 27 (Reuters) - The European Union on Friday moved to reinstate COVID travel restrictions like quarantine and testing requirements for unvaccinated citizens of the United States and five other countries, two diplomats told Reuters.
Not sure why schengenvisainfo left this detail out but perhaps for clickbait? Again we shall (hopefully) see tomorrow what the details are.