The WW server for my integral calculus class last term handled over 1.5 million transactions. In many cases, there were submissions from several students in the same second. Perhaps this explains why a tiny but nonzero fraction of the lines in the files answer.log and transaction.log seem to be corrupted. Details and discussion are available over on GitHub, which might be the right place for them ... if this anomaly is something in-scope for the WW developers. But maybe the root cause of this issue is elsewhere (in Apache, in the file system, etc.), in which case the broader group of experts here on the forum might be interested.
I regret lacking both the time and the knowledge to do much more with this issue than report it and hope someone takes an interest. If that describes you, wonderful! Please address other experts here, or navigate over to GitHub to see where the issue sits right now. Here's the link:
Thanks and regards, Philip