[Mixchump]

I've been having this exact problem as well. I'm finding the AT Pro (vers 9.0.1.0) to very buggy with repect to certain bits of correction data (curves, lines, etc.) to cause horrendous DC blasts, and/or crash ProTools entirely.

The problem the OP has described, where trying to scan goes over a certain spot that causes an instant crash has been driving me nuts lately. Most times, I can scan the phrase, but then when I play back the same spot, I get instant crash.

I've also had this thing where I scan a certain line, between other lines that I've already tuned. I can see it drawing the waveform and the pitch detection on the screen, but when I stop, it's gone! I tend to tune-while-comping the vocal - meaning that, once we've chosen the comp, I'll scan that line and tune it right away to make sure that we all like the result.

The workaround I've been doing lately, is that if I re-scan the entire song, that seems to fix the missing section stuff - and makes it MUCH less crash-prone.