Weird. I've had no trouble reprinting boarding passes just before flight time at checkin counter, lounge, etc (assuming I was validly checked in my the cutoff time, and that the requisite counter was open). An outsourced/outstation thing, perhaps, conveniently conflating "the flight is closed and we can't check in new people" to "we've logged out of the AC system for the day"?

That all being said, it is generally prudent to check one's boarding pass and take a screenshot or include in wallet so you aren't dependent on connection at the gate. Not due to this, presumably rare, situation, but since any number of other things could go wrong with boarding passes or your data connection, and you don't want to be That Guy (or Gal) holding up the line at the gate as you try to figure out why your data connection has conked out and so can't load your BP!