The GIF from that website has 40 frames in it, running for (hand-stopped) ~3 seconds, so it isn't really indicative of "how it looked in theater" (24 frames / second). It's exaggerating the issue. But the issue exists.
Three things come into effect here:
One, framerate and timing. Movie framerate, back then and today, is 24 frames / second, with ...
Snopes have done the research.
This video clip purportedly showing actor and martial arts master Bruce
Lee playing ping-pong with nunchaku (also called "nunchucks" or "nunchuks") is a digital creation intended as a viral advertisement for the Nokia N96 Limited Edition Bruce Lee cell phone, produced in 2008 (thirty-five years after Lee's death) [......