Looks like libtommath has now been fixed: https://github.com/libtom/libtommath/pull/57
On Sat Oct 08 14:47:40 2016, timo wrote: > Apparently libtommath is known to leave some bits 0 when specific > conditions for the defines are met; i haven't looked but i suspect we > are hitting exactly this problem: > > https://github.com/libtom/libtommath/pull/56 > > not sure why it's been quiet since april. >