Here is a sure fire way to avoid the wrong character bug while playing online.
When you choose a character and press Start, you will see 2 screens.
First screen is "Searching for opponents" with a Circle button showing "Back".
Second screen is "Opponents Found Connecting to opponents".
The bug happens if the second screen fails and it automatically goes back to the first screen to try again. At this point, you have a small window of time, to press "Back" and go back to character select.
If you don't do this, there is a random chance that once it goes back to the 2nd screen the 2nd time, you may get a character you did not choose.
If you press "back quickly enough on getting the first screen (the 2nd time) and go back to character select, you can avoid this bug.
This is bloody annoying, but it works reasonbly well. For me 100%, when I actually manage to hit the "back" button in time. Sometimes I fail to hit it in time because I'm distracted etc., and I mostly end up with the wrong character.
I hope SuperBOT can fix this bug. In the mean time, perhaps this will help some of you to avoid this bug.