This is very likely to be fixed in -current by this commit: https://marc.info/?l=openbsd-cvs&m=160993335615698&w=2 diff here: https://marc.info/?l=openbsd-tech&m=160992433912265&w=2
To get coredump and backtrace in such a situation, read up on kern.nouidcoredump=3 in sysctl(8)
