It seems to me that the offending dialog would only be triggered if you did a full fresh install. During the previous iteration of the testing, they probably had a VM somewhere with it installed; since the underlying packages were already present, the dialog would never have popped up.

Ubuntu 16.04, dual booted on my laptop before I knew how much of a hassle that could be! Fortunately, never had any of the infamous issues.

A new iteration of open-source drivers for NVIDIA cards which aims to work better and be more feature-complete. Original announcement post here which explains a bit better.