The burial site is actually a good encounter.
This is Encounter A4 in Keep on the Shadowfell. It's one of the places that players can go after their first visit to Winterhaven. An explorer named Douven Staul has gone missing while checking out an old dragon burial site, and the players need to uncover his fate.
It turns out that module overvillain Kalarel has some of his minions excavating the burial site, and these minions have abducted Staul to help in their work. When the players turn up, the minions will initially attempt trickery, before eventually trying to fill the players full of stabs.
One of the reasons it's good is because it makes a change of pace. It's yet another ambush, but at least it's not kobolds this time. The map helps, too, presenting a tactically different environment from the "road through the forest" that the players have already seen twice.
What's important about the burial site, though, is that it's out of the way. Players coming here get the real sense that they've reached it through their own initiative, which makes for a valuable interlude in the kobold-killing railroad that they'd otherwise be engaged in.
The blessing of the burial site is also its curse. There isn't really a lot of reason for the players to come here. The module offers some suggestions, including starting one or more players with a quest to find their "missing mentor" Douven Staul, and it's always possible that the players could hear about Douven and the burial site in Winterhaven and investigate out of pure curiosity. But it's an awkward way of integrating this location into the adventure, especially considering the burial site is a long hike from Winterhaven.
There are other problems with the encounter. Describing it as a "dragon burial site" raises some expectations, chief among them being dragons, undead, and hordes of loot. The players aren't going to find any of those things here, and the artificially high perceived challenge level might put them off coming altogether. DMs would be better to call it an "old dig site" or somesuch.
The enemy motivations are also problematic. The module shows them looking for an "ancient Nerathian mirror" for Kalarel, which they have actually found. However, the mirror isn't magical and there's no clue as to what, if anything, Kalarel wanted it for. PCs are left "guarding" an item that they're sure is critical to Kalarel's plans when in fact the villain couldn't care less what happens to this piece of junk.
The encounter as a whole feels like it was added to the module late in development. It's got a generally tacked-on feel and there's little reference to it outside the two page encounter description.
But it's a good example of how even a poorly-thought out encounter can still be a success if it's exactly what your game's pacing demanded.
 Four of the six colour battle mats included in Keep on the Shadowfell, including this one, are reprints of maps from the D&D Miniatures Game. Did this encounter only take place at a burial site in order to fit with the map?
 Keep on the Shadowfell already has less treasure than the core rulebooks suggest for a level of this length. Changing the "ancient Nerathian mirror" to a "thundering longsword +1" would fix a loose plot thread and a loot shortage at the same time. Is there any reason they didn't go down this path?