I was a solid 12 hour drive away from the location where it was occuring, so traveling was out of the question
pfft, lack of commitment.

The key problem is that I can't reproduce any of this.
OK, waxing philsophical for bit: if it's that rare is it worth fixing. Especially since it sounds like it's an ancillary function that's really just a "nice to have" rather than a necessity for the system to operate. If it's only going to happen twice in the next four years then you can probably just ignore it. If, on the other hand, the underlying tech has changed and you're going to start seeing it alot then it's definitely worth fixing, but then it won't be as difficult to replicate either.

I guess my advice would be to hang fire for a bit and see how many more instances you get. From what you've described it sounds like you probably are going to see a few more instances but you should also be able to gather some extra information that might help you solve it. With the info you've got currently you really are reduced to reviewing the code and posting futile threads which is probably not a particularly good use of your time (which could be more productively spent arguing about orcas). When something like this comes up having a quick code review is a good idea but if you haven't spotted the problem in the first hour or so you're just not going to. Instead you'll just end up reading the same few lines of code again and again to no avail. Don't let this become your whale, Ahab.

Besides, there haven't been anywhere near enough cheese based puns in CC lately.