Unknown GFX problem [Android]

Hello, I am very new to UE4 (come from Unity5) because of cascade.

Anyway I was playing around making a fire particle, compiled it to .apk and it ran on my phone fine.

All of a sudden after making the fire different (no detrimental tweaks just minor to what I had already (colour over life etc)).

Now my game looks like this?

What the potato?

Any help would be appreciated!