The last edition of the Watchtower (Study Edition) says the following:
Alexander the Great later conquered much of the ancient world, and common, or Koine, Greek became an international language. Many Jews began to speak that language, leading to the translation of the Hebrew Scriptures into Greek. This translation, thought to have been done by 72 translators, became known as the Septuagint. It was the first translation of the Bible and one of the most important. The work of so many translators resulted in varied translation styles, from literal to rather free. Nevertheless, the Septuagint was viewed as God’s Word by Greek-speaking Jews and later by Christians. ........
It is noteworthy that when writers of the Christian Greek Scriptures quoted from the Hebrew Scriptures, they usually did so from the Septuagint. These quotations, which at times vary somewhat from the exact Hebrew wording, are now part of the inspired Scriptures. Thus, the work of imperfect human translators became part of the inspired Word of God, a God who does not favor one culture or language over another.—Read Acts 10:34.
(The Watchtower, December 2015, page 5, paragraphs 5 and 9)
Interestingly, the Watchtower is stating that "the Septuagint was viewed as God's Word....by Christians" and it "became part of the inspired Word of God" though it was "the work of imperfect human translators". Furthermore, the Watchtower admits that the Septuagint "at times vary somewhat from the exact Hebrew wording". So, in other words, the Governing Body is saying that an imperfect translation can result in an inspired work.
Let's read some Septuagint's errors:
The virgin shall be with child and shall bear a son, and they shall call his name Immanu-El. (Isaiah 7:14)
The Septuagint mistranslated the hebrew word "almah" (young woman) by the greek word "parthenos" (virgin). So, Christians misused this verse so as to "prove" that Mary was virgin after conceiving Jesus.
Another example is Hebrews 10:5,6, where the author of this NT letter quoted Psalm 40:6 form the Septuagint:
However, the Hebrew Bible says:
Sacrifice and offering you did not desire. But you opened up my ears to hear. You did not ask for burnt offerings and sin offerings. (Psalm 40:6)
Note that the phrase "you prepared a body for me" is absent in the Hebrew Bible, but the author of the letter to the Hebrews quoted this Septuagint's verse conveniently.
Now, note the following Matthew's trick :
So Joseph got up and by night took along the young child and the child’s mother and went into Egypt. He stayed there until the death of Herod. This fulfilled what was spoken by Jehovah through his prophet, saying: “Out of Egypt I called my son.” (Matthew 2:14-15)
Matthew quoted the phrase “Out of Egypt I called my son” from the Hebrew Bible in Hosea 11:1, because the Septuagint reads "out of Egypt have I called his children". So, in this verse the Septuagint was not God's Word according to Matthew.
Do you note how this stuff is a mess???