How bad is it to overheat an engine during the breakin period?

Some of you may have seen my other thread here, where I found out my BRAND NEW 2015 RZR 900-S was missing a voltage regulator.
http://www.rzrforums.net/rzr-s-900/1…ese-plugs.html

Anyway, my main concern is that I overheated the engine when it was so new, with about 12 miles on it, and about 2 or 3 hours.

I cant remember what the max temp was, basically the temp light came on, and within a minute or two the engine started to sputter and loose almost all power, I shut it off after about 3 or 4 second of it sputtering.
It was boiling over at that point.

I know that the RZR has some builtin protection to shut it down at high temps so it doesnt damage itself, but since it was such a new machine and still during breakin, just how bad was this? How concerned should I be?