"one" means a constitution class, the Defiant, which has been modified in the 100 years since we saw it in Enterprise. Not a true constitution class, and not the actual Enterprise, which this thread is talking about.
I was referring to the Enterprise itself, and Captain Pike, Spock, Number One, etc.
No, this makes zero sense. The crew of the Discovery did not see an updated ship, they did not do a double take, they saw a modern Constitution. The only confusion was over it being from their future as they knew where the ship they saw was. Not "that does not look like the defiant" we got a "Put she is on patrol in x sector right now"
Zero confusion.
What ever we see, will be the constitution class of the cage era.