Humans are strange creatures
Not strictly speaking an IT issue, but it fits in with the general trend of denial / feigned ignorance.
Decades ago I was working for a quango and in one corner of the office a floor box fuse started regularly blowing and knocking out the kit on a bank of desks. There was much investigation, switching to alternative floor boxes, splitting the kit between different floor boxes etc, but we never got to the bottom of it and were unable to reproduce it ourselves. Then the problem seemed to go away.
All was finally explained when an office junior chose her leaving drinks as the ideal time to name and shame her team leader for plugging in a hot-air fan heater which would run for a while and then blow the fuse.Turns out that this individual knew not to use the heater, so hid it out of sight before I or the facilities manager arrived to investigate. Why her staff, who must have been pretty pissed off by the outages, never dobbed her in is another mystery.