More likely the model has a system prompt authoritatively saying what "now" is, and it can reason about other times specified in other resources in the training set because those resources specified their own time reference.
So even though a training resource said "It is DATE today. An IMPORTANT THING happened.", it knows that IMPORTANT THING happened in the past, because it knows CURRENT DATE from the system prompt, and it also knows that DATE < CURRENT DATE.
I see, So there is like a hi8gher level of facts/sources which are marked as such by the creators of the system. Higher level "facts" override the ones acquired from the public.
So even though a training resource said "It is DATE today. An IMPORTANT THING happened.", it knows that IMPORTANT THING happened in the past, because it knows CURRENT DATE from the system prompt, and it also knows that DATE < CURRENT DATE.