Even though I was not able to reproduce the error report via instrumentation, I did fix a bug which should account for this issue. The fix is in Mercurial changeset e3d167dbb186.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I am not able to reproduce this issue with ASAN or valgrind compiling using GCC 4.8.4. I am not able to reproduce it using clang 3.5 with ASAN.
Regardless, I think that I see a problem ...
Even though I was not able to reproduce the error report via instrumentation, I did fix a bug which should account for this issue. The fix is in Mercurial changeset e3d167dbb186.