Fuck, could have sworn they were The Berenstein Bears. I even remember my 2nd(?) grade teacher reading these books for us... and I don't her remember saying reading "BerenSTAIN". Pretty sure I would have remembered thinking "WTF" if I had heard that.
I have NEVER heard anyone say "BerenSTAIN" out loud ever. My mother loved the Bear books, bought loads of them, read them to me, and she said "Steen". So far LoneSiege is the only person Ive heard that remembers it that way from childhood. He and I are about the same age too ~30.