My favorite time bug: Someone on a team I was on spent probably weeks working on a way to process an inbound sensor data stream (which was generated by another

My favorite time bug: Someone on a team I was on spent probably weeks working on a way to process an inbound sensor data stream (which was generated by another bit of software also maintained by us). The data was akin to an odometer, increasing over time based on usage. The trouble was there appeared to be two parallel streams of the same name, which were always offset from each other and while the offset varied they were always roughly close. The algorithm this person came up with eventually sorted them into "thing_1" and "thing_2" streams, at which point it got turned over to me to display. It actually worked pretty well, for what it's worth. I started asking how am I supposed to show this to a user to make use of, what does this even represent?... but never got an adequate answer. So I started looking at the whole chain, and what I found was the piece of software generating the data had a small bug: it used "hh" instead of "HH" in the timestamp, but also no am/pm. The timestamps were supposed to be 24h and looked like it, but 9:02AM and 9:02PM both came in as "09:02". To confirm, we checked the database and, sure enough, every bit of data was between 1:00am and 12:59pm. In the end we fixed the timestamp bug and threw out the processing code. It's simultaneously a hilarious date bug, a face-palming colossal waste of time, and a lesson on how not to run technical teams (the manager had no technical skill, and the "team" of ~7 was very siloed and each operated more like teams of 1-2).