@Seriouscollector420 -
As
@Stu said, the temperature does swing above set, then falls below, and cycles like that if no draw is taken
As
@invertedisdead said, if no decent draw is taken, and conversation distracts session, units manufactured for the past 2 years (approx) will auto shutoff in 2 minutes, with brief warning buzzes beginning at 1 min 50 sec
I just ran a test with two units, both of the newer style. Set to max set temp 410F. Did not draw and let the temp swing to see maximum. Ran twice on one unit, consecutively, then once on other unit. They both behaved remarkably similar, swinging from 408 to 414. Only exceptions were during initial swings, which went up to 415 twice, and down to 407 a few times
You said yours vibrated differently. Want to make sure you were aware of the new, improved timeout vibration warnings on the newer Mightys. If you knew about them, and it buzzed weirdly, something doesn't sound good
You said your temp went up to 415-418, which definitely does not sound good, at least compared to my two. Thought perhaps a hot ambient setting would matter, but the internal sensors don't care how hot the room is. There are error codes listed in the manual, numeric, but you didn't mention one
My advice is open an RMA via their site
Or, you could try a reset, by holding down power button for ten seconds. Then try again, hope it was a fluke. But, S&B usually send a new replacement quickly on units that are so new, like yours