Not exactly true, since they also engaged in their own bit of textual criticism to try to reconcile variants in the text. For example, they chose "sons of Israel" over "sons of God" in Deu. 32:8, though the latter reading is favored by the DSS, the Targums, and the LXX. They also noted what they considered spelling errors in the text as they received it with qere-ketiv notations (which just shows their honesty, since it would have been far easier to just "fix" the "errors.")
However, such variants are extremely few and far between and I don't believe any of them actually impact any text of the Tanakh quoted in the NT. (Feel free to correct me if I'm wrong.) I don't know of any that impact any point of halakha either--though of course the sages debated on which vowels to use for different words and even where the spaces between words should go in the Talmud.
Shalom
Yep, and those "spelling errors" are still there . . . probably because they're supposed to be.