The only episode I ever remembered was the one that took place in at least two different parallel universes:
About Luthor: They actually did explain the difference in appearance between the first and second versions of the character, didn't they?
Donald Draper wrote:
I am not sure when the reverse \S/ was introduced but when Bizarro first appeared he had exactly the same costume as Superman. It was that way in all his 60s, Silver Age stories.
It might have been Superfriends
the cartoon series, which always depicted Bizarro with a backwards S.