Hi Jordi,

available stock quant is reserved from stock moves. You can find and delete open stock move lines e.g. in Inventory -> Reporting -> Product Moves -> Remove all default filters and e.g. group the records by status -> delete all not needed records which are not done

I had this same type of problem and I'm not sure of this since I am really new but when I did see it the pull location was different than the location where the stock was.   This may be some sort of location problem.