SM has indicated there are known issues with queue rendering and using multiple runtimes in a scene. These should be fixed in the next Service Release. These problems are apparently intermittent so there is no real way of predicting when the problem occurs.
This is all new stuff for Poser so this is the area where one could have expected problems, there are some more problems reported with the queue. So we will have to wait until these problems are fixed. Still it does work sometimes and when it works it helps.

Overall few problems have been reported, so I think P7P is a fairly stable release and most new features appear to work as intended.