I dug up a pic of some Dubble I had that did the pink thing, it was also extremely close to a 600w hps and got a bit bleached at the top as you can see.
I also had the Glue go pink on me. I tried out an Agrosun Super Red HPS, plants that don't normally color up get a beautiful fade under this bulb specifically.. Makes me want to get my Dub cut back and run her under the Agro sun's...