Ultimate Intrigue requires Advanced Class Guide and Advanced Player's Guide, which are included in the Pathfinder RPG for Game Masters package. The ACG and APG cannot be added if you already have the PF for GMs package, so Ultimate Intrigue says it is incompatible.
I have zero issues with master (6.09.x) and 6.08.00 RC7.
Okay, old multiset… Why aren’t you using the newer version? Pathfinder RPG Core Supplements