Monkey Grip should be included in the Fighter's Bonus Feat list. For me, it makes sense as it is a Martial/Combat Feat.
I releveled a character that was almost level 16, so I could remove Brew Potion. After I got to level 16, I had to relevel it again because Monkey Grip wasn't an option as fighter Bonus Feat and I had forgotten to get it at level 15. The character had it before the relevel.