If I understand what you are saying, it only occurs when you run dcheck with mutliple
volumes at one time?
I can't say I EVER did that back in the pre-fsck days.
We did icheck and then dcheck on each disk in sequence.
I don't even think we had a shell script. It was incumbent on the operator to
check each of the system disks and any user volumes that were mounted at the time the
system crash.
Bugs are entirely not uncommon. This is why BSD and JHU and UT had their own
distributions. Having been a V6 UNIX systems programmer at a university back in the
day as we had students who found it an extracurricular activity (nobody took computing
seriously back then) to break security or just plain crash the system. Tons of worse
bugs than dcheck issues.
I actually spent some time before they elevated me to system programmer doing some
exploration in to problems (authorized by the staff).
I decided to test all the setuid programs against vulnerabilities of playing with the file
descriptors before invoking them. I found a half a dozen problems and mailed of the
details before I decided to give up and go home. The next morning our log had a message
about the first eight characters of the system accounting file being corrupted. I told
the guys recovering from that that I might know how that had happened. They said they
figured I would because it was my user name that was found overwritten on the file.