This happened to me on September 5th on the Central Line and I'm still thinking about it. I'm posting here because it fits the simulation theory framework.
I was at Oxford Circus station waiting for the eastbound train. The announcement said it was arriving in two minutes. But then I got distracted and stepped away from the platform edge to check the departure board more carefully.
When I turned back around, the exact same train (same number visible on the front, same slight graffiti mark on one window I'd noticed) was pulling into the platform behind me - the westbound platform, opposite direction, about 20 metres away.
Time stamp on my phone showed only 90 seconds had passed. The train couldn't possibly have looped around the line and come back in that time. The routes don't work that way. It's the same physical train in two places at once, basically.
I got on the eastbound one (the first one) and got off at my stop fine. But that moment of seeing the identical train on the opposite platform... it felt like a rendering error. Like the system had duplicated an object.
Anyone experienced anything like this? Simulation glitches where the same thing appears in two places simultaneously?