All Bible translations have mistranslated passages. That is a given. They are human productions after all. For this installment, we are going to look at a passage where the translations are mostly correct because they mistranslate their source text. That passage is Genesis 12:15.
The Masoretic Text version of the passage (without the vowels) is:
wtqḥ hʾšh byt prʿh
The King James Version translates:
and the woman was taken into Pharaoh’s house.
This makes sense, but the question is whether it is translated correctly. The answer is yes, and no. The translation does not translate what the source text actually says, which would be:
and the woman was taken Pharaoh’s house.
The Masoretic Text is actually ungrammatical here and this is a result of a transmission error which dropped a single letter from the text. If we were to conjecturally correct the text, we would probably emend it to supply the missing preposition as follows:
wtqḥ hʾšh lbyt prʿh
Doing so would correct the grammatical error but would also be wrong. The Samaritan Pentateuch has the correct reading:
wtqḥ hʾšh byth prʿh
The use of the locative he here is an archaic feature of the language, particularly when it is used in construct as it is here. It supplies the missing preposition.
So the King James Version correctly translated the passage by tacitly correcting the grammar mistake in the Masoretic Text. I do not know what was going through the translators' minds, but it is possible that they did not even notice that there was an error in the grammar at that point in the text. They knew what the text must mean even if that was not what their source text actually said. From one point of view, their translation was wrong, but from another it was correct.
How do the other translations fare?
ESV: And the woman was taken into Pharaoh’s house.
NRSV: And the woman was taken into Pharaoh’s house.
NIV: and she was taken into his palace.
NLT: and Sarai was taken into his palace.
NKJV: And the woman was taken to Pharaoh’s house.
NIrV: So she was taken into his palace.
Not a single one of these versions translated the text that they said they were translating. The NIV, the NLT, and the NIrV are particularly bad.