The chest near the Blacksmith Survey site in Eastmarch (35.03/29.35) is unreachable -- it's sunken into the ground, buried beneath the snow. My antiquities passive shows me that it's there but it can't be interacted with.
Sometimes moving away from the area of the chest, doing a /reloadui, and moving back into the area can help-- but I've had more luck with that in dungeons than in overland.
I've seen this myself a few times, and I wonder if it's possible that the chest itself might be located in an underground cave that is just under the surface of that area? Just a thought?