Talked with @mont29 on IRC, summary
There is no bug here, you are merely suffering from precision issues (you know, floats…) - your objects (curves) have extreme offsets (like -500 for median point of a curve's control points in local space), this generates small errors that add up to give imprecise 'conversion' from mere objects to dupli ones. Thanks for the report, but nothing we can do here.
Thanks for first review. :)
Code its self seems OK but some design am not sure about. (could read patch in more detail but think its reasonable to make design obvious up-front).
Can confirm the issue here (linux, GTX850m, nvidia drivers 340.65). Antony, is it known glitch from changes in draw code?
Seems to be windows specific issue, still cannot reproduce the issue on linux, even with an asan build.
Closed by commit rBA3b6028fd8b89.
Can confirm crash with egg_crash file on Windows x64.