LSAC doesn't remove very many questions from scoring because they don't screw up very much. The SAT removes a lot more questions from scoring partly because there are more SAT questions per year (7 tests per year, 170 questions per test vs. 4 tests per year, 100 questions per test — though the SAT also repeats tests/questions much more often than the LSAT does) but also partly because the SAT-makers screw up a lot more than the LSAT-makers do.
It is extremely likely that every LSAT question that has ever been removed from scoring was challenged based on the memory of an individual test-taker. The test-taker gets really irritated about the question, spends 2-3 minutes on it, fumes about it during the break, fumes about it again after the test, and probably fumes about it during the other sections, too, which drags the test-taker's score down. Then he or she calls LSAC after the test and complains about question 5 in section 3, or whatever, and LSAC starts its investigation. Rarely does that investigation turn up that the question is flawed, but occasionally it will.
So there's nothing wrong with challenging a question, but only about a half-dozen LSAT questions have been removed from scoring in 20 years of LSAT, so your odds are not good — and it's possible that fuming about any individual question throughout the whole test is an unnecessary distraction anyway. Let someone else challenge the question; you've got a test to take.