Try changing the Z-index for your position of red.go’s sprite to 1. I think this might be happening because your main.collection’s sprite has ‘Add’ blend mode and they’re on the same z-index.
Also, unless you have changed your render script, your objects will only be drawn from -1 to 1 z. You have high precision in that range though. If you have multiple objects that need to be drawn in a specific order, you will want to change their z-positions by very small numbers. 0.01, 0.02, 0.03, or something like that.