This is interesting. I was working on a job and notice all the new wiring they ran was stranded
Typical of the quality wiring jobs you get these days. Hacker bought cheap wire off probably ebay and didn't have a clue. That stranded wire is for making patch cords, NOT premises wiring. You can't punch it down on the jacks or patch panel. It may work for awhile but it's going to be nothing but intermittent trouble.
-Hal