I'm not sure if anyone else has seen this, but I often find that IR restarts\recalculates when I zoom in with the scroll wheel on my mouse in the VFB the first time. Subsequent zooms in or out don't do this until the next time I stop and then start IR. It's not a huge deal, but on big scenes it can be kind of annoying.
It's not scene dependent so I don't think there's any use in uploading a scene. I'm using Win 10, Max 2016, and the latest Daily (but it's been happening for a while.)
Thanks,
Daniel