YouTube has restored some videos of robots fighting after wrongly removing hundreds for displaying a “deliberate infliction of animal suffering or the forcing of animals to fight”.
Sarah Pohorecky, of MIT, said film of her robot So Rachet removed on Monday “mysteriously reappeared” on Tuesday.
A YouTube spokeswoman said: “With the massive volume of videos on our site, sometimes we make the wrong call.”
YouTube would work quickly to reinstate the other videos, she told BBC News.
Jamison Go, a research assistant at MIT (Massachusetts Institute of Technology), said he had lost nine videos but others had lost hundreds.
“Today is a sad day,” he said on Monday in a Facebook post.
“Robot builders across the world cried out in agony as YouTube’s algorithm falsely identified personal videos of robot sport as ‘animal cruelty’ and ‘cock fighting’.”