The boots on mine started to flake a year ago too. i think it has something to do with humid weather or something that makes the material dry and brittle. i have been very careful when posing him since then.
Interesting about the boots - most modern pleather seems to have problems, and HT has had quite a few of their products' pleather go septic. It's the reason I prefer sculpted boots.
We have quite a bit of humidity in the summer but I either run the A/C unit in the collection room, or a dehumidifier, which works well if it's only humidity and not heat and humidity at the same time. You can also place those moisture absorber closet type products in the back of your display cabinets, which constantly absorb humidity. They aren't that attractive, but I usually hide them as best I can.
The two issues I had with my fig were that the PERS eyes had a small plastic sheath around them that started to fall down into the eye itself (ie become visible in the eyes) - almost like the backers that hold the eyeballs in place had come loose. Managed to get them out and cleaned up okay, but it was a little scary.
Be VERY careful moving the eyes and don't reposition them too much. I was fascinated by the PERS (had never seen one before) and changed the eyes maybe ten times in the first couple of months and just had a gentle play with the system in the first week - that was probably what did it.
Other issue is the tiny fragile clips that hold the jacket and pants closed broke after undoing/redoing them only a couple of times (to pad the upper chest a bit.)
The belt does fall apart (I've only had one pocket come loose, but others have reported more significant unraveling), but its pretty easy to re-glue.