I just tried with Mac OSX 10.9.3, 50 frames of a moving cube, saving as Quicktime MOV. This was compiled from source (x86_64 arch) with code from last week (technically, 2.71 from 7/19). No crash, and I was able to play back the MOV. Also, not that it is probably a big deal, I can't find any attached *.blend files.
*UPDATE: I just saw that this only happens in 32-bit builds. Please ignore my comment!

This appears to happen only while Cycles is actively rendering. I changed the preview sample count from 0 (unlimited) to 20. Once the integration/rendering completes, this doesn't happen.

Last comment.. I promise.. ;) How can this be converted into a feature request that simply gives the user the option for something like "Path Folding" or "Corner Compensation" behavior? I'd hate to lose track of this one. It seems like if this were implemented as a simple selection (with the default being "no matching" or "no compensation"), that it would solve the underlying issue as well as give the user the option to have it either way. For architecture models, it seems the current behavior is definitely not very desirable. Plus, the code already seems to work both ways.
Thanks again!

I hit this exact same thing. If this is desirable behavior, how can we achieve a more natural 90 degree turn when using the bevel shape on a path?