I have the exact same problem. I have Bonds 1.3.1 from DLSite and it keeps progressively getting slower and slower in Session mode, until it takes literally seconds to react per click. Only completely quitting and relaunching the game fixes it. This is a quad-core x64 CPU with 16GB RAM mind you, so really, this is not about the hardware. And I don't remember having this problem at all in 1.2...