Chord of Calling mana inconsistencies.

Gargoyle

So I've noticed that Convoke and X values don't combine correctly.
Someone mentioned that some related issues were resolved previously but as I'm experiencing this bug consistently I'm assuming that was a separate issue.

Basically Convoke is only reducing mana cost up to it's Max value if it is part of the original cost and not the X value.  
So if you charge Chord of Calling up to 9 with an empty board the X value won't move a budge from playing any Creatures.

Even if you were to argue they are separate values the Convoke value lowering the actual mana cost must therefore have a flow-on effect; if less of the stored mana is going towards base cost the difference should count for X. Or does it just disappear?

Gargoyle

I've also noticed that if you use Sarkhan Unbroken's Sangrite Overlords ability to fetch and charge a creature with Convoke(Arboretum Elemental in this case) then reduce the number of creatures on your board the card will get drained of it's mana even though it was fully charged originally. 

Tombstone

Convoke is only intended to reduce the base cost of the card. If a card already has full Mana and its cost is reduced by convoke, the excess Mana is lost and will not be converted to Stored Mana. This is the intended functionality. 

Regarding the interaction with Sarkhan Unbroken's Sangrite Overlords, if the fetched creature comes into play with its cost reduced by Convoke and you then reduce the number of creatures in play, it's cost will increase again meaning that it will no longer have full Mana. 

Gargoyle

Tombstone said:

Convoke is only intended to reduce the base cost of the card. If a card already has full Mana and its cost is reduced by convoke, the excess Mana is lost and will not be converted to Stored Mana. This is the intended functionality. 

Regarding the interaction with Sarkhan Unbroken's Sangrite Overlords, if the fetched creature comes into play with its cost reduced by Convoke and you then reduce the number of creatures in play, it's cost will increase again meaning that it will no longer have full Mana. 

Hmm, well it would be nice if that was clarified in the text.
It's ambiguous IMO. I guess Convoke isn't really the problem; a card with Stored Mana can't have it's Mana raised(which you could certainly argue is what happens in my 'flow on effect' premise) but by that logic the first 1 Mana to contribute to X could still be given by summoning a Creature when X=0. Prior to that the card has no Stored Mana and is capable of having its Mana raised. Don't think this is the case though, by my experience.

There's also the weird occurrence that if the 'base cost' is filled exactly by playing another Creature(ie X=0) you can play it for 0, but if it's filled exactly by charging it can't be played for 0 and gets the 'unplayable' icon. So there's something mixed up, even if it's not quite what I anticipated.
So either '0' Stored Mana counts as having some Stored Mana, under all circumstances, and you can always Fetch a Creature without charging it via Chord's effect(0x3=0 after all), or you should get a 1 mana start on your Stored Mana when playing an extra Creature with a partially charged Chord of Calling that's at exactly 9 mana.

The answer you give in relation to Sarkhans 3's ability makes sense though. I guess I was thinking they're given full mana before they're technically in your hand, but it's a sequence thing not a genuine concern, sure. Definitely separate to the other stuff anyway.