Honestly it depends on the mod and mod maker. Flaking paint isn't the most UNUSUAL thing of all time. Keep in mind the Ares is not painted (at least not yet) so it doesn't really have paint to "flake off" which, again may not be unusual depending on type of paint, how much eliquid gets on there, how often you are washing it, changing it from mod to mod or whatever . Some tanks are just painted, and it's not done very well, others use a clear coat or some way to "Fuse" the paint to the mod, etc. and that may hold up better.
IDK that tank so I couldn't say for sure if it's "within normal" but I'd imagine possibly? Paint does flake but if it's not inside the tank, I'd say it's a cosmetic issue at this point. I guess your options would be to strip the paint completely or to live with your ah, "distressed," tank.
Anna