I had the same experience...someone on the BK Discord shared this link, which I found pretty interesting https://fillamentum.com/pages/drying-filaments-before-processing/
Key take-away: cooling the filament after drying needs to be done in a controlled environment, i.e. put it in a zip lock bag with desiccant immediately after its taken out of the heat.
I have used my oven on the lowest temp but it really stinks up the house. I just realized that my food dehydrator basically does the same thing...worked out awesome