Board Thread:Help Desk/@comment-89.101.119.41-20130408100718/@comment-7700568-20130408154230

This is a known bug. Try talking to The Guide near a Tinkerer's Workshop and showing him the Hermes Boots or the Rocket Boots (through the Crafting option on dialogue), he'll probably show you the recipe to craft the Spectre Boots. This bug also happens with other items, and it should be bypassed by simply talking to the guide and following the same steps.

Hope it helped. xD