This is not reproducible with 6.3.0.2, which is still just a release candidate of soon-to-be-released (and will-be-new-fresh) version 6.3. But you use development build of current master toward 6.4 (which will only be released next February) - not even alpha 1 - which is actively developed, with expected lots of bugs, which only get polished close to release… so - well, you are on your own using that. It would be nice if you do something to find the roots of the problem (e.g. using bibisect tool) or - even better - fix that (joining developers). But not much more that you could expect here.
By the way - I confirm your observation with my build of master.