Why was Mitt Romney initially incorrectly reported as the winner of the GOP Iowa caucus in 2012?

Question

I keep reading this bit that Mitt Romney was initially incorrectly reported as the winner of the GOP caucus in 2012, but I can't seem to find much in the way of details why that happened, e.g. in WaPo:

In 2012, it was the Republican caucus that was a mess. Back then, Mitt Romney was named the winner of the caucuses by eight votes — a narrow victory, yes, but still a victory for the favorite to be the Republican nominee.

Romney went on to win the New Hampshire primary comfortably, apparently winning the often-elusive double in the first two contests — he would have been the first Republican to ever win both Iowa and New Hampshire — and setting him on course to face incumbent President Barack Obama.

Except eight days after that New Hampshire win, we found Romney actually finished second in Iowa. The Iowa GOP announced, 16 days after the caucuses, that Rick Santorum had actually finished first — by 34 votes. But even that result was tinged by uncertainty:

Santorum’s strange, belated victory also served to embarrass the Iowa GOP — which had to admit that it had misallocated some votes, and simply lost some others, in a razor’s-edge election where every vote mattered.

It also cast an unflattering light on the old-fashioned and convoluted system that the party uses to collect and count caucus votes.

What exactly were the reasons for this failure in 2012? There was no app then...

Answer 1

What news I could dig seem to point to a lack of proper paper trail in some places and plenty of typos...:

There are too many holes in the certified totals from the Iowa caucuses to know for certain who won, but Rick Santorum wound up with a 34-vote advantage.

Results from eight precincts are missing — any of which could hold an advantage for Mitt Romney — and will never be recovered and certified, Republican Party of Iowa officials told The Des Moines Register on Wednesday.

GOP officials discovered inaccuracies in 131 precincts, although not all the changes affected the two leaders. Changes in one precinct alone shifted the vote by 50 — a margin greater than the certified tally.

It’s not a surprise that the ultra-thin gap of eight votes on caucus night didn’t hold up, but it’s tough to swallow the fact that there will always be a question mark hanging over this race, politics insiders said. [...]

Strawn explained why the certification took longer than he’d hoped: Not every county filed complete information. “Our staff played the role of Columbo, going around the state trying to track down wayward precinct results — and with few exceptions very successfully,” he said. [...]

The biggest shift happened in Fayette County. In two cases there, Rick Santorum gained more votes than the entire gap in the statewide certified total.

FAYETTE
Caucus night tally: Mitt Romney 241, Rick Santorum 174
Problem: Typos in two precincts. A reported 54 votes in Illyria township
should have been 5, and 54 votes in Oelwein’s third precinct should have been 4. Another wrinkle: Four precincts’ Form Es were signed by the same two people when party instructions call for individual precinct leaders to sign each form.
Certified result: Santorum 172, Romney 136

The other two major examples given also involved typos.