"These are strong moments."
Translation:Ce sont des moments forts.
I agree that moment and instant are synonyms, but I would still say that, depending on context, they may mean slightly different things.
To me, an "instant" in time is always instantaneous or very short-lived by it's very nature. A "moment" in time may also be very short-lived, like, "It happened in a moment". In that sentence, one could use moment and instant pretty much interchangeably.
However, I could see how moment could be used differently and it is how I see it being used here. A moment could refer to a period of time. So, "These are some special moments" seemingly refers to unspecified periods of time that may be instantaneous, or, more likely, probably not instantaneous. Like, if you went to a concert and it was a very memorable one, the entirety of the concert did not occur in an instant, but, it could more readily be referred to as a moment of time that you would remember.
So, I think it would be valid to not say that instant and moment mean the same thing in this translation. That is just my opinion though, and, like I said, I definitely agree that they are synonyms.