There have been 3 times on 3 different AAMC tests where I got a significantly lower score than avg on a section, and when I went back to recheck, my answers were different from the answers I originally selected. On some of those questions I eliminated all BUT one answer and remembered selecting the one that was left, but when I reviewed the test, w/e answer choice I remember selecting got changed to some answer choice I had eliminated, so I would get that question wrong..it was pretty weird and it happened multiple times
Not really sure if this is the error you're talking about, or if the scoring problem you mentioned is that the AAMC test made a mistake when it was counting up your incorrect answer choices. But I know the AAMC tests do have some glitches (like with the 'estimated amount of time spent per question' column)