The Berenstain/stein thing is a weird one for sure. I wish I'd saved one of my kid's books so I could check for myself. The only thing I can offer there is that I pronounced the name "BerenSTAIN". If I had seen it spelled "stein", I would have associated it with names like Frankenstein or Einstein and pronounced it that way.

I find the concept fascinating. I wonder at times if one of those CERN projects actually split our reality into 2 streams.

Another possibility is that it's part of a (very) long-term psyop that started somewhere back in the late 80s. One part of the population gets the media spelled one way, the other part gets it spelled the other way. When they grow up, you'd have a group of adults that would have 2 different memories of the same thing, both believing that their version of history is correct - and they'd both be right! I could see psychologists being very very interested in a study like that.