Here is a similar story from the childhood of computers: One of the first computers installed in a Norwegian university was of course in high demand, and students generally had to stay up at night to be able to use it. One morning, around 3 o'clock, the line printer came to a a halt and locked up the computer. They tried everything they could think of to get it going again, to no avail.

In the end they called the person in charge of the computer. He came over and closed the curtains, and the printer started up again. He left without a word of explanation.

That explanation emerged later: The early morning sun (the sun rises early in the summer here) was shining in, through the paper in the printer, onto the out-of-paper sensor, making the printer think it had no paper. Closing the curtain fixed it.