This is quite theoretical, and I hope it's the right SE site.
A couple of years ago I worked at a company using Maya 2014 (I think that was the version) with a couple of other 3D Artists.
Eventually I figured out that there's a short, reproducible sequence of operations that I can do that will lead to the crash of the program without fail - 100% rate, with a catch.
The Sequence, for the sake of completeness:
Open a fresh Maya, create a polygon cylinder, set the rendering style of the perspective style to shaded if it isn't already, press space twice to get to the side view in wireframe, select all faces, deselect the middle faces, delete the (now selected) caps, select one of the border rings, extrude and pull out the edge, press 3 to set the cylinder to smoothed rendering, then press space to leave the wireframe side view. At this point, the other views would fail to render, Maya would encounter a fatal error and close itself.
I could perform this on any PC, with any Hardware, on a fresh or highly modified Version of that Maya without fail. The catch: Only I could do it.
When I showed this bug to my colleagues and they tried to replicate it, Maya did NOT crash. (I think there was one other person to which this also happened, maybe) We could perform the sequence on the same PC on the same install back to back, it would crash for me but not for them.
We theorized it might be that I'm typing faster than the others, confusing the system. I performed the steps slowly yet it still happened. The sequence was also only the fastest way to replicate the crash. "Tabbing out of a smoothed wireframe view after performing an operation in it" was the only condition, and all projects would crash on me if I didn't pay attention to the conditions.
What we did NOT test was what would happen if I would perform one half of the sequence and a colleague the other, trying to narrow it down to a certain step.
So, the bug occurred reliably: - Independent of Hardware - Independent of it being a fresh install - Independent of context (big or small project) - Independent of operation speed - Apparently, dependent on the person performing it.
I jokingly called it the "Curse of the Maya" and we left it at that - but to this day I wonder, what could theoretically cause a bug to appear seemingly dependent on the user? From all my understanding of software that just doesn't make sense.