There are a number of timelines, but they all show basically the same thing:
Someone in the Carson camp tells CNN that Carson is "leaving the campaign trail to return to Florida" and will not be heading to NH or SC. They either tell CNN or CNN discovers that Carson has no campaign events scheduled for the next several days. CNN tweets this information out and it is discussed live on air.
The Cruz campaign sends the information out to its team, recommending they urge Carson voters to vote for Cruz instead.
At some point Carson sends out 2 different statements saying he is staying in the race.
CNN sends out another statement saying Carson is "taking a break" from the campaign AFTER Carson has sent out the clarification.
The Carson clarification is not forwarded to the Cruz campaign staff.
Keeping in mind this happened over a very short period of time (30-45 minutes from most of the timelines I have seen) and the amount of activity and chaos that was present with record numbers of caucus goers, I can kind of understand how the Carson clarification got missed by the precinct captains. There were dozens of tweets flying around about Carson going to Florida after the original CNN report from different sources, but only 2 tweets with the clarification. And even CNN was still tweeting the original story AFTER the clarification.
Was the Cruz campaign HQ wrong to share the original story and use it to persuade Carson voters to vote for them? No, that was fair game. Even if they told Carson voters that his actions made it look like he was getting ready to quit, there is nothing wrong or unethical about that. Everyone who viewed the original report seemed to have the same idea - it DID look like he was getting ready to quit. If they said that Carson had announced he was quitting and they knew it was false, that would have been wrong.
Should the Cruz campaign HQ have forwarded the clarification from the Carson campaign to its staff? It really was not their job to clean up Carson's mess, but it still would have been the right thing to do. The fact that did not happen is why Ted apologized.
For some reason, the Trump supporters want to say that it was up to the Cruz campaign to check the story before they shared it, and that it was their responsibility to correct the story when it turned out to be untrue. No, it was CNN's responsibility to get the story right in the first place, and it was the responsibility of CNN and the Carson campaign to correct the false impression afterward. Helping them to do so would have been a nice thing for the Cruz campaign to do, but during the caucus, their job was to get their people to vote for them, not help another campaign.
I have not seen any detailed timelines on whether or when the Cruz campaign saw the clarification from the Carson campaign. The Cruz people forwarded a CNN report. This was in the midst of the caucus process, when everyone was running around in hair-on-fire mode. I am quite sure they had tv's showing the news reporting. I doubt they were sitting around monitoring twitter feeds from all the other campaigns. Unless Ben Carson picked up the phone and called Ted Cruz personally, or his campaign manager talked to the top Cruz person, there is no reason to assume the loop would be closed.