It looks like "PDB sync" is failing due to some interaction with IoCoroutine.

It's reproducible just by running the PDB unit tests:

> > make testaddons
> ...
> Obsidian - testBasic
> testSimpleSync
> IoCoroutine error: unable to auto abort coro 0x1005ca050 by resuming parent
coro Object_0x10022a7d0

I'm not sure when this broke, but PDB and its unit tests did work fine as of a
few months ago. I've entered a bug in the GitHub tracker. I'll look into it if I
have the time, but with any luck maybe someone with more experience with the
coroutine code can point out something obvious.

- James