That's interesting and it's becoming apparent that this concoction can have a mind of it's own. Here's what I mean...
I received a bottle from richy with the 601/501 mixture. It performed flawlessy both in cleaning ability and alone had decent durability, about 3 months before zero beading occured. I still have half a bottle left and it's just like the day richy sent it to me. However,...
...when it arrived and I opened the bottle (inside my wifes office to smell the product) there was a minor issue. The bottle richy had sent the mixture in had a screw on black cap with a read stopper underneath the screw-on cap (great way to ship a product actually because it can't leak). Apparently the concoction had built up pressure inside and when I went to pull out the red stopper, when I almost had it completely out, it shot out of the bottle like a rocket with a mist of product flying through the air. Nothing real major as far as the mist, and no one got hurt. There was no mixture to wipe off of anything other than a dab on my pant leg and hands. Actually, I thought it was sort of funny, but I was also glad it didn't send viable amounts of liquid shooting all over the place or into my eyes. I've heard of this happening to other folks as well, and then some have had no issue with this happening. It's odd that some experience some sort of reaction, yet others don't.
My point is, either by pressure build up inside the bottles on occasion, and now with your report of it turning a funky color and hardening along with my product remaining viable a year later, this stuff seems to have a mind of it's own as far as any reaction after mixing is concerned.
The above two "events" don't really cause me to take anything away from the product, nor would I not recommend them or stop using them as a result. One thing is for certain, regardless of discoloring or not, hardening or not, "explosive" (not really, just a pop) or not, the mixture is very predictable in how well it will clean, shine, and protect.
Either way, BobbyG's suggestion of mixing on the pad will work great, or mix up only enough product in abottle that you will use in one setting is good advice and doesn't waste a good product.