It is strange to see the same NPC that is located in town (Forest Haven and Balefort Castle).

The Xmas Thief spawns and sells L100, 105 Elite items, for 250-500 Platinum.

So I believe the thief actually has a reason to be there. As for the NPC vendor Gusty, he still has the same dialogue and no differences to the one in town.

A lot of us PL players are confused.