This is not issue, for them it is the nature of premium tires. Coz in order to get comfort and better braking distance your rubber compound need to be soft, then softer material will be easier to chip wear off. If you dont want to see this condition, just buy those cheap budget tires from Indonesia or Thailand where the rubber compound is harder and you will know the disadvantage (which is opposite of what premium tires does).

I have used from Michelin, Bridgestone, Pirelli, Continental & even Yokohama tires also same. Ask tires shop, luckily is my best friend he told me treads are made to wistand the harse road condition if still within safety limit just use it unless got serious crack on the side wall or inner treads (long deep cracks). The rubber only chips off on the edge and not whole tire piece drop off and below still got so many layers (do you know how thick is the treads?!?) before consider dangerous to drive.

If you never been in track/gymkana racing, those chip off are nothing and mostly driven until tread near finish (reach safety level) and change. FYI, in order the tire to be in dangerous or burst usually is either over or under air pressure, tread wear finish until can see the metal mesh (that is the most dangerous limit) as metal mesh will heat up and melt the rubber and burst (u can see tires got a lot of sparks, flames and smoke before it burst). To drive until this extream limit, you need a lot of balls to drive the tires without treads (really botak)