That's to do with your polygons not being entirely planar individually. Smoothing groups would solve most of that, but yeah, it's generally a good idea to make sure you don't grab one vertex of the 4 in a polygon, and move it off - that's what would cause this in most cases.
"Viewport issue"... You know that at the end of the day every ngon or any amount of sided polygon is a triangle. Apply smooth, enable autosmooth, and set the threshold to 0 and you should get this in any max version, or in the most of the modeling applications, when there is no smoothing, unless they do something that is aware specifically of triangulation smoothing, which most likely isn't the case. Especially because this way at least you can see if you need to flip a few triangles on your lowpoly here and there to make them doing bridges and stuff.
It was a display performance optimization the 3ds Max team added. There is no fix for Max 2017, but Max 2018.1 added Model Assist viewport mode. Which gives the smoothing (the old behavior) at the expense of performance.
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https://help.autodesk.com/view/3DSMAX/2018/ENU/?guid=GUID-E36FEE48-05A5-4C95-929E-2CFD8D0B7FA3