You set the transparency to 1 up until Time=0.8, so since the lifetime is (5,5), it’ll take 4 seconds to start turning visible
I’m not sure how you want it to look, but you could try starting at Transparency=1, then changing to Transparency=0 at Time=0.1, then leaving it at Transparency=0 until Time=0.9, then changing to Transparency=1 at Time=1