Honestly, this is a pretty funny bug for how I handled it on the backend because I specifically researched how to handle this situation and selected the (now obvious) wrong option.
That reminds me of when I got a requirement (that was due before it was handed to me) to add two files of input into my code and also handle them. I'm not saying it was hard at all, but I was rushing. Now I wasn't dumb enough to do no file error handling, but when I put in a check to make sure I wasn't handled an empty file, I skipped the nice error handling (cause they promised me it wouldn't be empty) and just put down a cout of I don't have time for this shit, for the first one and, I don't have time for this other shit, on the second and skipped the empty file.
I finished linking in the other code and my lead was excited to see if I had saved their butts, so they all gathered around my machine to see how the first test case went.
I was horrified to find out I had reversed my greater than and less then signs and my error handling code was tripped on the non empty files, and all my coworkers watched my monitor spit out a pair of somewhat profane error messages, while I turned increasingly red.
(authors note: a swap of the signs and a recompile led to a successful test and everyone forgot about the faux pas in the new hope of meeting the deliverable)