TNG "Conspiracy"
In the beginning, worf describes the Horatio as an Ambassador-class starship.
Yet late, he says that the debris field, judging by it's size, could only be the Horatio. As if there is only one Ambassador-class ship. And that it's more massive than any other starship. Yet later in the series we see that the Enterprise-C was an Ambassador-class and that it was a little smaller than a Galaxy class. Also later on we discover that there's lots of Ambassador-class starships.
I remember watching for the first time years ago. And thinking that the Horatio must be some type of dreadnaught class. And the Captain, Walter Keel, seemed to be a senior Captain.