PLAY PLAY MY GAME TESTERS. PLAY THE UNPLAYABLE VERSION OF A HIT GAME UNTIL YOU DISCOVER EVERY LAS T BUG. MU HAHAHAHAHAHAHAHAHA!
Obviously the testers for Sonic 3 were blind or had their eyes shut.
Tails should have been left alone after this point in development though, it would have been kinda funny to see him walk through walls in the final version (and I have seen him do that every so often in both beta and final versions of Sonic 2.)
I remember I was playing and Sonic got stuck in rolling position... this was on Sonic Jam, and I never found out why it happened... never really cared. Temporary invincibility. :D