When multiclassing Brawler and Monk, it appears that Brawler levels count as both Brawler and Monk levels for the purpose of base attack bonus. That is, a Brawler 18 Monk 2 has a base attack of +33 (which is Brawler's  + Monk [.75*20]) when it should be 19 (which is Brawler's  + Monk [.75*2]).
This might have snuck in when making the Brawler's and Monk's levels combine for unarmed damage dice. (A Brawler 2/Monk 2 should gets 1d8 damage.)
Windows 7 and Windows 10