There's a quite serious problem about how, by taking the correct timing in using a mystery, is actually possible to make them impossible to be interrupted.This issue makes mostly useless, in top level arenas/matsuri/spacetime finals (where people know what to do), any interrupting ninja like Iruka or Neji even on non prompt moves like sasuke's or haku's barrier.
*
this is the proof of what i'm saying, thanks to Eplox that recorded it: https://youtu.be/T-Y5WDDYPn0
*
And if you are thinking that going on Auto would solve it, the reply is a big NO, because even by going on Auto the program that manages the game isn't quick enough to react to our swiftness in pressing the 'auto' *on (if we select it too early the AI uses the interrupting mystery during the previous ninja turn or wastes the interruption on the lowest hp ninja if the enemy doesn't use the mystery, if we use it at the correct time still doesn't work because the program takes its time to understand you want it to go on auto and skip the whole action during while the enemy uses the mystery you would want to interrupt).
I don't know if this is a bug or not, but is a very serious issue, overall for people that don't won the best PC in the world or that dosn't have the best possible connection (but doesn't change much even if you sit on the Pentagon mainframe and on a 10Gb/s connection).