Satyr flesh requires 10 pieces to combine, tooltip shows 9. Impossible to combine 9. Bug is happening during Ten Pounds of Flesh quest (https://www.wowhead.com/quest=14358)

Sadly, this is unfixable at the moment.
This feature utilizes Blizzard's Tradeskill API to get the "recipe" info, but sometimes the required number in the database is -1 than it should be. I haven't figured out the pattern yet.