Did my Dr. Make a Mistake? Found Out One of my Implants Are Upside Down?

and I do not believe your doctor made a mistake.  But why did you switch doctors in mid-stream?  Implants can turn upside down if the pocket is large enough to allow movement of the implant.  As for muscle release, that is a judgment call and something you should have discussed with your doctor before the procedure as to how much improvement you would be achieved in diminishing your distance between the breasts.

You did not mention if you used gel or saline filled implants.  One of the problems with saline filled implants is that if over filled they tend to get very round and can definitely rotate in the implant capsule.  All implants have a definite front and back and are designed to be placed in this manner.  The only time I have seen this to be a problem is when a thin patient has an overfilled saline filled implant.  In this situation there can be a subtle change in shape.  No negligence or deviation of the standard of care is involved.