Max randomly freezing for 1-2 minutes at a time on scenes with visible Forest Pack objects

Has anyone encountered this problem? I should note that it only happens if the Forest Pack objects are visible. If I put them in a layer and make it hidden, I don’t get the freezes. Admittedly I’m using the latest beta of Forest Pack (so I can render with Vray Next Beta) but the problem started about a year ago while I still had my old Intel i7 workstation and was using official/stable versions of FP only. Now the problem seems to persist with my new workstation. It happens even with extremely simple and light Forest Pack scattering configurations with just a few hundred scattered instances of 3 objects. It is also happening on another PC here (same hardware and software except for the graphics card and display drivers). Any ideas what could be the issue?

I had this for years and was never able to solve it, even after changing my workstation. I tried sending scenes to iToo but they could not replicate the problem.
It is very annoying but I learnt to live with it by displaying FP objects only when I need to.