As noted above, the bug severity was upgraded too late to stop 0.5.2 migrating.
There have been a series of releases since, and while this bug was mostly fixed in 0.5.3 it appears there were still some edge cases. The code is still fairly fast moving, and in the end I don't think it's a good candidate for a stable release at this time; I'll aim to provide a version in stretch-backports in due course.
