The maker at Korilla Boots in Busan has a neat way of handling meltable thread ends when bottoming: cut them long, light the ends aflame, press and smear them down, then hammer. Here’s a direct link to the time offset on YouTube: https://www.youtube.com/watch?v=5ysPDWv2ws0&t=21m33s
I could see that holding especially well, first since the melted ends cool around a lot of fibers, second because it creates a kind of fan-shaped tab with more surface area for the cork bottom filler to adhere to.