have an old Power Source Gauntlet in your market mail (or, if you're REALLY old, a Power Ranger Glove)
make sure you have an open stash slot, then retrieve the mail
the website will tell you that the item has been successfully retrieved, and placed in a specific stash slot
view that stash slot. you can do this in one of several ways: via the in-game Oracle UI, through the stash button on your roshpit.ca profile page, or by refreshing the Your Sales page and browsing your inventory in preparation to list another one of your items for sale
observe that the slot listed does not contain your Power Source Gauntlet, but is instead a blank slot. if you are in-game and attempt to make changes to this item slot - either by dragging and dropping another stashed item on top of it in order to switch their places, or by dragging and dropping an item from your hero's inventory onto the slot in an attempt to swap them - the Oracle UI will darken, as it attempts to execute your stash operation, but it will never un-darken and the stash operation will fail. you will need to close the Oracle UI or change to the Key Bank or hero save data tabs in order to restore the NPC's functionality.
STEPS TO REPRODUCE: