Liner problem

I have a 2 year old 18x36 IG with a vinyl liner and I've been using the BBB method since late spring of this year. Within the last 6-8 weeks I've noticed the liner fading but mostly in the shallow end. Maybe fading is the wrong term...it looks like sprinkles of white salt on the bottom. It's not debris that can be vacuumed up, either. I also see white scuff marks (that's the best way to describe it) in a few areas. It's all confined to the floor of the shallow end--nothing in the deep end or on the side walls.
I'd suspect undissolved chemicals causing the white specs, but I haven't used any kind of powdered products since early June. When I add bleach, I usually add it in front of the jet in the deep end but lately I've been pouring it right into the skimmer. I have a high CYA level (about 90) but have had clear water by keeping the CL at around 5-10 ppm and I can't recall getting it up to shock level since switching to bleach. My ph has been between 7.5-7.8 all season.
I compared a scrap piece of liner to the one in the pool and there is a little color loss, but it doesn't seem excessive for the second season of a pool that sits in full sun 90% of the day.

The liner is PosiTrac Vinyl made by Vyn-all. Here's the actual pattern. (pretty cool, huh?)
It's not noticeable from the surface, but it appears to gradually be showing up in more places.

Has anybody else seen this? Any chance that there's a magic 4th "B" that I could add to undo it? (Bullion, Barbecue sauce, Butter, Beer? These are just guesses, but I'll try 'em if you guys think it'll help.)

With enough beer, you probably would not notice the discoloration anymore, or at least not care if you did notice it! :D

I'm no help on how to solve your problem, but I love that liner!!! I came so close to picking that one out when we had our pool put in. Really neat :)