I'm melding materia onto my crafters and have been for a while, but recently - like post lv70 I've noticed that materia stats start to cap red.

For example:

On a pair of Swallowskin Shoes I have 2 Craftsmans Command VI materia. The first is red capped at +11 and the second at +0.

But on my Dwarven Cotton Jacket I have 2 VIII's and they arent capped, which seems inconsistent.

Is there some kind of overall stat cap going on? Basically, is anyone able to explain whats going on with this?