ZigzagPX4
The Swiftness of the Ranger
Funny you say well designed,
I had that location break on me, despite killing all the hostiles, and the location being marked as [CLEAR] on my map, the quest still told me to eliminate all the hostiles.
Well-designed as in, the way the backstory for the settlement was set out and the level design inside the building with the mirelurks, plus the atmosphere of the place as a whole. It certainly isn't very revolutionary, but it's one of the best locations in Fallout 4. By best, I mean most functional, and least stupid.
The location breaking on you isn't because of the place per se, it's because of the shoddy scripting of the enemies and what to mark off as soon as they're dead. That's not location specific, it can randomly happen with any settlement clearing quest.