https://www.youtube.com/watch?v=4DOvSYlQacE

Corrected link.  

Yes, those masteries can absolutely mess things up. You DO NOT WANT ANYTHING that can alter your move order. Cycle of Revenge is probably the number one way people mess up CB. Rapid Response and Cycle of Magic are probably the number two and number three way.

As for the video - link doesn't work. My guess is you posted the link from your own internal studio, and not the publicly published one.

I upgraded the link.  

If I remove those masteries and replace them with something random will that solve the problem?

So, yes, you do need to do that, but no, that won't solve the problem. The reason you are dying is because whoever the green-affinity person on the left is, is taking too much damage. You'll notice in particular that when ATK down drops off, and when the boss gets ATK up, everyone elses shield is growing, but his eventually starts getting smaller. If you start watching around turn 20 you can see it pretty clearly, and turn 22 he loses one of the two shield buffs, after which things go downhill much faster.

There's a few solutions, but the simplest one is to just give him more DEF so that the shield doesn't fall off.

I built Hotatsu (4733 def) to replace Ronda (3566 def).  He lasted longer but still lost his shields.   

https://www.youtube.com/watch?v=2ST8Xl66_uM

Wasn;t the problem Malkith's def is too low, not ronda's?

You can see in this one that on turn 19, your leftmost champ loses the shield set buff. That'll cause that champ to eventually die, as they lose the double-shield-growth. Guessing that's Ronda.

Again - I said this a few times, but you need to understand that damage is NOT a priority here. All you need to do is survive. Literally just from Warmaster/Giantslayer alone, you'll easily get 1-key. Drop Ronda, replace her with someone who can consistently place ATK down, maybe even someone who can bring more buffs to the team - Strengthen for example, or Continuous Healing so that you have more buffs. Hotatsu doesn't help because his ATK down is only 75%, and his CH only lasts 1 turn, so at very least one person will lose it before it can be extended.

I did drop Ronda.  I replaced her with Hotatsu and enough def he should have survived.  

I may not have any champs who can do that.  I went over my list.  I will go back over them and see what I can find.  I focused on dec atk in the last search.  Will expand to the buffs you suggested.  

Wix has 9 buffs now and the others have 7.  How many more do I need?

Thanks for being patient.  

Do you have demytha?

nope he doesnt .. would any other continuous heal stack like demytha ?? Would Ursula work ? Does she uses her a3 even if no dead ally(like ukko a3) ? would push the buffs .. 

Yes any 2 turn version works. And ursala is another atk down too.

from what i've seen and chat about with poly.. someone dying early is always the issue ... even when they have plenty of def/hp .. no bad masteries to interfere .. not set to mess up the order .. 

im thinking .. Wixwell , Brogni , anchorite , malkith and ursula ? What preset would be required if using that team ?

Honestly, I'm really quite confused as to why the team isn't working as-is. Like, I spent almost zero time building mine out. Maybe it'd help to compare? I'll post team screenshots. In terms of presets, there's nothing terribly fancy going on - Demy, Brogni, and Wix all have A3 on opener + disable, and that's it.

Demytha

A2 Increases the duration of all ally buffs by 1 turn, then decreases the
duration of all ally debuffs by 1 turn.  Also heals all allies by 2.5% of their MAX HP. Heals by a further 2.5%
MAX HP for each turn added to or removed from the duration of buffs and
debuffs by this skill. 

A3 Places a [Block Damage] buff on all allies for 1 turn, and a 15% [Continuous Heal] buff on all allies for 2 turns. 

I dont have anyone with all of Demy skills.  I am still sorting champs to see if I can find 2 who bring what Demy brings in total.  

You don't need any healing if the shields don't fail

Any champ with a buff extend should work

Can I run 3 buff extenders plus Wix and Brogni.  I am running out of ideas.  

I don't see why not

As I said - Demy A3 is on opener + disable. All she is doing is buff extending. The heal is irrelevant since nobody is taking damage, and the debuff duration reduction is irrelevant since nobody is being debuffed. Similarly, Sandlashed does nothing special beyond just buff extending, since her passive will never trigger.  Having a 3rd buff extender doesn't help, since Wix already does that job.

One thing I did notice is that Geomancer passive might be helping a fair amount. 15% damage reduction is nothing to sneeze at. You could try running him on the team, or possibly someone like Venomage with a similar passive. Or even someone like Helicath or Roshcard for block damage, to make the shields take less damage.

Helicath, or Geomancer as DPS, is a good plan