It's a pretty mundane glitch but about time I shared it somewhere. Happened a few days ago.
On a day like any other I was sent off to yet another Cable TV installation. The ticket showed that this premises had already had it installed at one stage so with a bit of luck I could just install the box and get out of there. After being greeted by the customer and doing the usual chit chat I got to work and put in their shiny new cable receiver. Everything seemed to work ok but when I tested the signal with the meter and it was a bit low though. I knew the previous install was a 2-box setup so I decided to remove the splitter to get the signal up to spec. I climbed up onto the roof, pulled back a tile, located the splitter, and disconnected the second outlet. I'd done this plenty of times before in similar circumstances.
I went back down to make sure everything was ok and there was no signal. Obviously I'd somehow mucked up removing the splitter, or perhaps it had been installed the wrong way round in the first place, so I get back up to the roof and switch leads.
There was still no signal. This was weird. I took the meter up to the roof with me and tested all three lines. No signal, not even a weak one, just nothing coming through. I traced the line all the way back to the isolator box to find it's not connected there, it's just hanging loose outside the box. I have to run a whole new cable to where the splitter was. I'm annoyed because it's taking longer, and I'm freaked out because there is no way that the box should have been working when I first tested it, ran the system update, and activated the smartcard/box combination without it being connected.
The rational explanation doesn't satisfy my sense of logic, but I'm happy to admit that I don't know. Better than making up bullshit, anyway. Hopefully this is the most disturbing glitch I ever encounter!