Nathan Doak’s boot had given Ulster a 9-3 advantage at the interval, but the South African side scored four tries after the break meaning Ulster ended their mini tour in the Rainbow Nation with a solidarity losing point from two games.
Skipper Iain Henderson believed there was a combination of factors such as playing at altitude, individual errors and officiating decisions that contributed to the poor second-half showing.
“Honestly I think it was a mixture of all those things,” stated Henderson.
“We talked about the start of the game and I though we managed that really well. At half-time we talked about how they would be pretty fired up coming out for the second half, being at home, being down after the first half.
“It was something we spoke about but didn’t manage as well as we could have,” he added.
“Again, a couple of refereeing calls that we have no control over, altitude... when the Bulls get their backs up, their off-loading game - all those kind of things sort of peaked against us in the second half.”
Expecting a huge physical battle up front, Ulster went for a six forwards and two backs split on their replacements bench but that was thrown into disarray when winger Ethan McIlroy had to be replaced by Stewart Moore with barely two minutes on the clock.
“Going into a game everyone with the exception of the front row are probably expecting to go 80 minutes and definitely looking to push through,” said Henderson.
“So when you have that mindset within your team it shouldn’t really affect you; you should be sticking to your own game but a bit of altitude, different conditions maybe it does (affect game plan) but I’m not 100 per cent sure.”
Ulster now must regroup and get ready for the away and home games against defending European Champions Cup holders Toulouse.
He said: “We know we have put hard work in over the last fortnight and the buzz and excitement will start to grow this week as it always does around the European Cup.”