What about the white edge of PPR water pipe cutting?

What is the location characteristic of the silver stripe phenomenon?

One of the characteristics of the site of the silver streaking phenomenon is its reversibility. It can disappear spontaneously above the glass transition temperature of the material, which is called "self-healing". So, if you take a heat gun and blow it for a while, the silver lines will disappear naturally.

It is normal for PPR water pipe shears to have white edges

It is a normal physical phenomenon that PPR water pipe shears have white edges. If your scissors are sharp enough, or if you cut fast enough, to minimize the lateral stress pulling during the cutting process, the silver streaks will be much less noticeable or even invisible.