Protect doesn't fail in single battles when it isn't the first thing done (for example when the opponent switches out or uses an item); not sure how this canonically works in doubles
While walking around in the east side of Neo Gearen, my team randomly reset to where it was a couple of levels ago, including writing in pokemon I had deposited into the PC over pokemon currently in my party (so I got some duplicates and permanently lost some pokemon.) This happened pretty soon after I used the glitch to deposit one of Ren's pokemon in my PC, in my first time in Neo Gearen