I think i understood what is your problem, so let me explain a thing that maybe you aren't aware of.

The general rule qoolem talks about is the following one: in pvp a first prompt move mystery can be interrupted only by a first prompt move mystery if has higher initiative, a second prompt move mystery can be interrupted only by a first prompt move mystery or by a second prompt move mystery with higher initiative, a third prompt move mystery can be interrupted by a 1st or 2nd prompt move mystery or by a 3rd prompt move mystery with higher initiative, and so on. But beware that this is the general rule.

The game mechanics are made in a way that if you don't lag and have the best pc in the world and you don't use any mystery then what happens is that you get the following streak of actions: 1st: highest initiative first prompt move ninja uses his standard attack. 2nd: lowest initiative first prompt move ninja uses his standard attack. 3rd: highest initiative second prompt move ninja uses his standard attack, 4th: lowest initiative second prompt move ninja uses his standard attack and so on up to the 4th lowest initiative prompt move ninja. The time span between one action and the following one is set and when you use a mystery this timespan don't get at all modified nor the actions i talked about get delayed. Depending on when you use a mystery the effect gets displayed before or after one of these actions.

Now, the problem you are facing is the following one: a skilled player knows exactly about how this mechanics work and so waits 1 millisecond before his 2nd prompt move ninja standard attack lands to use a mystery if he knows it can be interrupted. By doing so, when the icon of the mystery pops over the ninja, you click on your mystery to interrupt the enemy, but the server don't have the time to understand that you wanted to use the mystery to interrupt your enemy one and so, for it, is like if you wanted to use the mystery AFTER the enemy second prompt move standard attack.

So what happens is that instead of getting the following streak of movements (the one you expect to get): your mystery -> enemy negated mystery -> standard attack, you get this streak of movements: enemy mystery -> standard attack -> your mystery. Just because the time between one standard attack and another is fixed and mysteries gets placed between them.

To be clearer: a mystery can be interrupted by a theoretically faster mystery ONLY IF BOTH ARE CALCULATED BY THE SERVER AS IF THEY ARE HAPPENING BETWEEN THE TWO SAME ACTIONS (standard attacks).

So, yes, a mystery, with some timing skill can be made uninterruptable and personally speaking i think this is a serious problem that could be easily solved in 99% of the cases by adding a line of code that says that when you use a mystery the following standard attack gets forcefully delayed by 2 seconds.

Theoretically automode should prevent this, but only if you are lucky enough to be on auto before the standard attack where your enemy choses to use his mystery, otherwise the AI will simply waste the interruption on the lowest hp ninja and beware that when you click on 'auto' the game doesn't switch immediately to automode, but waits for the following action to do it, making so very hard to take advantage of it in this specific situation.

That team is one of the very few teams where what i explained can be done even before the first prompt move standard attack because mabui have a passive that happens before each action that helps a lot for the timing before first prompt move standard attack. So what happens is that your enemy just wait for mabui to give chakra and instead of clicking immediately on tenten mystery (this would let you interrupt it) waits for another 0.5 seconds and then uses tenten mystery just before mabui healing standard attack, so, when you click on iruka to interrupt it you just passed the time the server gives you to place iruka mystery before mabui healing. Infact, when happens, you see that tenten lands the mystery on you, then mabui heals (for 0 hp of course, you just see the green aura around the highest hp ninja that tells you it happened) and then iruka hits tenten.

I explained it in the text. Read it better. Doesn't matter your initiative, he just uses his mysteries before one of his standard attacks and even if you have higher initiative you can't use your mysteries before his ones for the reason i explained. If instead you get nuked by a standard attack like sage naruto one that starts for sure a combo... i explained that too. Position on the field matters only on par initiative, (so in pvp only among summons/clones at the end of the round), but if initiative is higher than 0 then the highest initiative first prompt move ninja moves always before the lowest initiative first prompt move ninja, even if your one is in position 1 and enemy one is in position 6, to use the numbers of qoolem.

Let be clearer. Lets say i use this lineup:

x roshi x

yagura breeze dancer x

x sage naruto x

and my roshi have 4000 initiative.

Lets say you use the classic mb blitz team:

Mifune x MB

Wb asuma iruka x

x x x

And your mb have 3800 initiative.

Who moves first?

Reading what you wrote you seem to think that should move first your mb, but no, since both your mb and my roshi are first prompt moves then, moves first my roshi even if is in position 4 and your mb is in position 1.