Quite obviously!
The mistake wasn’t noticed, by anyone, until it was pointed out. Even then there was a difference of opinion about whether it really mattered, but,on balance, the Board decided it did because it failed to meet the BBC’s own high standards. There was no intent to mislead or harm anyone. They were reporting things that Trump said, 2 out of a huge number of things he said, on the subject. They could have put any number of them together, but all ought to have been marked as separate from each other. That was the accident. Either by an over enthusiastic journalist or, more likely, just overlooked in the cutting room at the editing stage.