I dont this Mei's yellow lava is a mistake!
Hi everyone. There seems to be a lot of discussion lately in regards to Mei's lava and its differing appearance.
Well I think there is a simple explantion.
I think the yellow colour is actually the correct colour. The way the lava looked at the kage summit (red/orange, fiery and viscous like actual lava) was a mistake.
If you look at the below image, the lava is thin and watery. Its not really lava in my opinion, more live a liquid version of Mei's boil release - some sort of chemical liquid that dissolves whatever it makes contact with. This new lava in the latest shippuden episode (watery and not orange/red) reflects this.
Also if you look at this picture, Mei's lava doesnt look all that fiery. Its light coloured with some darker coloured outline.
I'd also like to point out the different japanese kanji used for lava. In Roshi's case - 熔, using the fire (火) radical. In Mei's case - 溶, using the water (水) radical.
熔 - associated with solids, fusing and melting. 溶 - associated with liquids, soluble and dissolving.
Hope this helps