Which ones did you find that are under construction but missing from the Tesla "coming soon" map? I definitely didn't look exhaustively, but of the several under construction sites I checked, all had pins on the Tesla CS map. A fair number of "permitted" sites fall through or have long timelines, so that might explain why some of those are missing (like Clearwater, B.C.)...
Edit: Also, a lot of the "coming soon" pins on the Find Us map are buried under current supercharger pins. Kamloops even has 2 "coming soon" pins, but they're hard to see!