Not sure if this has already been brought up.
It appears that the verses in Matthew 21:29 and Matthew 21:30 have been transposed from one translation to the other.
The 'old' NWT in vs 29 & 30 states:
'In answer this one said, "I will sir, but did not go out"'. Verse 30 reads: 'Approaching the second, he said the same. In reply this one said, "I will not' Afterwards he felt regret and went out."'
The 'new' NWT in vs 29 & 30 states:
'In answer this one said, "I will not," but afteward, he felt regret and went out.' Verse 30 reads: 'Approaching the second, he said the same. This one replied, "I will, Sir, but did not go out.'"
All of "Christendom's" translations read the way that the 'new' NWT now reads. Apparently this is an error contained in the 'old' NWT. Christendom had it right all along. I don't remember any of the GB making mention of this correction at the AGM!