Apparently they need to be opened from the crossroads, Old Hand Scars, or Freshwater springs before they work two ways.
I spawn at a very distant location and pretty much rely on these paths to get to and from Mistlocke, but when I try 5 in a row and none of them work, I come to the conclusion that the 'random-mater' comes from Mistlocke.
Or I've been extremely unlucky.
Either way, this is a problem. :(
It pretty much makes some of us unable to interact with anyone on the server unless we walked across 10-20 areas of disgusting spawns to do so. The randomness of the Mist transitions are appreciated and cool, but I wouldn't think that an entire part of the island would be simply shut off to access (5 Mist transitions) after a reset due to it.
Actually, it looks like we were just extremely unlucky!
Six mist ways from the Forgotten Forest (which will always lead somewhere), 20 different destination possibilities. So of course a lot of the mist ways scattered around won't lead anywhere... this is all by design, and not a bug.
The Pass of Rabbanatha always remains open, or you could go through the mountains or even the Delving.