No problem. The
periapt of wisdom comes from D&D 3.5, the Adventure Path's original source. And you're right, the publication change switched the item from a periapt (necklace) to a headband, which is a different body slot. OGL, eat your heart out.
In my description of the item, I presented it as a pearl charm on the bullywug's bracelet
¤. Being used in this way, it would have used the bullywug's wrist slot. Whomever wishes to use it going forward may continue to use it as a bracelet, or fashion it onto a chain and make it a periapt (or necklace if they prefer), or another slot position.
Alternatively, it can be sold at half its market value, or "fed" to Gé for its complete (100%) market value in raw residuum.
Spoiler text: (Highlight or hover over the text to view)
¤When I was a teenager, I was really into the R.A. Salvatore novels about Drizzt Do'Urden. In Siege of Darkness, Drizzt kills his brother and takes a pair of enchanted bracers, which later cause havoc with his fighting style, as he becomes too fast for even him to fight effectively. Towards the end of the book, he puts them on his ankles to speed up his footwork. Ever since reading that, I've always been fascinated with the idea of misusing magical items. It was my thought that perhaps the bullywug didn't know what a periapt was either, and simply used it as a bracelet? This doesn't upset the rules, in my opinion, as the bonus remains the same, only the body slot changes, which seems to be a page out of Paizo's book anyway.
This message was last edited by the GM at 21:08, Sun 04 Sept 2016.