Head glows only while in spectator mode

While trying to make a machine in 15w35e, I discovered there was dragonBreath, wake and endRod particles. After playing around with them, I tried making myself glow for a second to see if the glow around me flashes. It didn't so ... I did nothing. I went on spectator, wondering if I would glow while invisible, I tried adding the effect and I was glowing. But only my head was. You could change the spectator form to a full body with major alpha.

/gamemode 3
/effect @p 24 1000000 255 true
F5 (x2)