Thanks for the heads up. Hmm, how strange. Does it look like that for you every time? Did you do any specific steps to produce the pink triangle? This is the first time I've seen this issue
I got it each time I loaded the WebGL version of the game. I grabbed the project source and built a Linux version, there it doesn't appear.
I had seen it on another entry and it appears to be connected to the PostProcessing volume. The other game had one at the position of the triangle, too...
