Putin's declared ceasefire became effective at 18:00pm, local time. At 17:15pm Zelensky made a speech saying he does not trust Putin and won't stopped Ukrainian military from attacking if they already planed to do it. What WaPo/CNN reported is Zelensky's talk at 17:15pm. At 18:00pm Russia side stopped all the attacks and there were no Russian drones in the sky since then. At 18:15pm, Ukrainian military received emergency instructions to stop all the attacks. Of course because of command chain issues some individual troops might not received the ceasefire instructions in time. But overall current ceasefire is going very well from both sides on a 1000 km long frontline. Using the words of soliders from front, "it's unprecedented".
The military analyst I followed got information from battle front, not from keyboard or internet.