Broken: (example: 2.80, edbf15d3c044, master, 2018-11-28, as found on the splash screen)
Short description of error
My goal was to add an edge loop and slide it down to tighten the corners of my glass when smoothing. When I add the loop and try to slide it down, it doesn't move all verticies.
Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
I've attached the file showing the results. To Repo, remove the highlighted edge shown in the picture. Then select loop cut to add the edge back. Press Shift V to slide the edge. At this point you "should notice the issue". I've tried several times but it keeps doing the same thing so I'm assuming this is a bug. I'm a beginner at modeling so it could also be something wrong with the model but I've looked into that and can't find anything.