Well, taking your advice this way:
self.vizi=CollisionVisualizer("visualizer")
base.cTrav.setRecorder(self.vizi)
...
def taskFunc(task):
self.vizi.output(panda3d.core.Notify.out())
return task.cont
Doesn’t make the program freeze, yet provides rather shallow information, no nodes are named and it only prints the number of detected collision solids and the number of tests conducted, e.g.:
CollisionVisualizer visualizer tested 3, detected 3
However, it strangely prevents this issue from erupting:
Which to me is strange. Maybe because by invoking
panda3d.core.Notify.out()
It somehow prevents other errors from being printed out? But I shall not speculate, best to wait and see if someone more informed on this will respond with the right answer. For the time being, it seems to have stopped that error from crashing the application.
Terribly sorry for hijacking your thread this way 
, but I just thought I’d highlight this.