You've been looking hard for errors in the NWT.
Here's one for you: John 14:14. The NWT says: "If you ask anything in my name, I will do it." The W&H text (as given in the Interlinear) says: "If you ask me anything in my name, I will do it."
I wrote to the Society many years ago about this, as I was unable to find any explanation for this in the publications. The answer was theological, rather than textual. The only thing I've ever seen since is the footnote in the Reference Bible:
*** Footnote ***
Footnote Rbi8 John 14:14
"Ask," ADIt and in agreement with 15:16 and 16:23; P 66 ?BWVgSy h,p , "ask me."
As you can see, all the oldest Greek manuscripts have the "ask me" in the text.
I searched the WT CD, and still couldn't find anything more.