I've seen many people dodge it while still being held in the attack, how do you do this, is it possible to stop or is it something I'm doing wrong?
It is basically if the chase sequence comes up before the opponent hits square then you can usually dodge out of it. This happens a lot in laggy situations. Auto recovery does it a lot of the button press is delayed at all, but you could always mash X if they seem to wait a lil too long.
Just a little lag and that's pretty much it. I fought against a friend once and i could dodge many other undodgeable things too. >_>
Meo Twister also seems to bug sometimes.
Unfortunately meo twister can be dodged out of under certain circumstances. As a zidane user nothing gets to me more than having meo twister miss or be dodged out of. Sometimes depending on the map it can be glitched and not hit the opponent but that is very situational. Other times when im battling a friend it can get a bit too laggy and so he doesnt get hit by it at all and sometimes he is just able to dodge it by mashing on x or timing it right. My best advice is to just hit square as soon as you are done with the brave attack, it leaves less time for them to dodge. Or you can return dodge cancel out of rumble rush or tempest (whichever one you used) and hit them quick with free energy.
I start mashing  as soon as swifts 2nd phase begins
yea, ive dodged out of it on several occassions because of lag....
oh and lol, ive also experienced being killed by a Meo Twister i had dodged out of xD dunno why..... (was nowhere near, but when the meo twister animation ended i got damaged and died)
Being in "Guest" has a significant effect on it.