I thought the OP meant that his/her ranger's bear was bugged
Actually they are a bit buggy, as they are obviously tempted by invisible honey-pots when you leave an area, and this honey affects their short-term memory - "duh what did you want me to do again?"
Back on topic - my first playthrough was a rogue also, and I did find this unstealthing a bit annoying. However, I did like the fact that it didn't allow me to reload before certain fights to get my party perfectly set up, forcing me to react more spontaneosly. Pretty easy to click the stealth button anyway. Not so easy to summon the buggy bear and get its tactics sorted though lol.
Also, if the rogue is the main character, well he/she has to do the talking, and it's hard to do that when you're slinking away in the shadows. "who said that? Show yourself you coward!"