Likewise all in work scenes, unfortunately. I'll have to see if I can reproduce it at home in a less-complicated setup.
It was definitely an issue across multiple earlier versions of Houdini, I don't recall which, but I feel like the range was somewhere in H17 up to about H18.5 as you note, and our entire team was seeing it. I never experienced it in any H19.0 build at all that I can recall, but it quickly became apparent again when I moved to H19.5