I've listed below all the withdrawn questions I found. If you flip to the appropriate page, all you'll see is a blank space with the words "Item Removed From Scoring" or "Question withheld from scoring." In the answer key, you'll see an asterisk (*) where the credited response would've been listed. As I said, LSAC doesn't publish withdrawn questions.
-PrepTest 23 (October 1997), Section 3, Question 1 (page 164 in 10 More Actual, Official LSAT PrepTests) - Logical Reasoning
-PrepTest 32 (October 2000), Section 4, Question 22 (page 144 in The Next 10 Actual, Official LSAT PrepTests) - Logical Reasoning
- PrepTest 38 (October 2002), Section 4, Question 12 (page 345 in The Next 10...) - Logical Reasoning
- PrepTest 45 (December 2004), Section 1, Question 5 - Logical Reasoning
- PrepTest 46 (June 2005), Section 1, Question 9 - Reading Comprehension
- PrepTest 52 (September 2007), Section 4, Question 15 - Reading Comprehension
- PrepTest 60 (June 2010), Section 1, Question 19 - Logical Reasoning
Admittedly, it's difficult to make any predictions with a sample size of only 7 questions. However, if the distribution of flawed questions on previous exams is an indication of where future flawed questions will appear, then flawed questions may be more likely to appear on September / October exams in the future.
I'm only speculating, but I suspect that as LSAC has tried to include more difficult questions in recent years, it has become increasingly likely to "cross the line" by including questions that had no correct answer, which were later removed from scoring.
The fact that recent years are the first time we've seen Reading Comprehension questions withdrawn is an indication that the Reading Comprehension section is becoming more difficult.
If you spot any withdrawn questions in your PrepTests that I missed, please email me with your additions to the list above. Thanks!
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