The Masoretic Text (MT) did not come into existence until some 700 years after the New Testament was written. As such, there is no possible way the New Testament writers could have anticipated differences between the Septuagint, which was available during their lifetime, and the Masoretic Text, which appeared long after they died.
Even considering the proto-Hebrew text from which the Masoretic Text is derived, I still do not think that we can assume that particular proto-text is the one that was extant during the time of the New Testament writers.
There are thousands of verses, for example, where the text in the Dead Sea Scrolls differs from that found in the Masoretic Text.1 In some cases it agrees with the Septuagint (LXX) and/or the Samaritan Pentateuch (SP), but not the MT; in other cases it agrees with the MT, but disagrees with the LXX and/or SP; in other cases it disagrees or agrees with all three. In still other cases, different Dead Sea scrolls disagree with each other. Thus, we cannot even be certain which particular Hebrew text would have served as a basis of comparison with the Septuagint. Given the vast number of differences between the MT and other Hebrew texts and the late origin of the MT manuscripts we have (11th century)2, however, it seems unlikely that the MT proto-text would have been the one against any such comparison would have been based.
1. See, e.g., apparatus of Abegg, Flint, and Ulrich, The Dead Sea Scrolls Bible (Harper Collins, 1999).
2. The oldest complete manuscript we have of the Masoretic Text is the Leningrad Codex, which dates to 1008-09 (AD). The oldest incomplete manuscript we have is the Aleppo Codex, which is a few decades older.