The save above show a glitch when you use NEUT inside the circle. Some of the NEUT becomes PHOT and passes though FILT and becomes blue. I didn't know if this had been mentioned before so don't flame me if so.
It's not really a gitch. I discover this last year already. The neut passes through glass creating photon that has the same color as neut then passes through glass to filter then turns out dark blue.