I don't know what plating you are referring to?
These are brand new from the package strings. The high E is missing plating and is rusting. When you slide your fingers across these spots it will rip meat off your finger. I have never seen this until the last couple years.
- From this phenomena, I assume strings are steel and plated with nickel. In these cheap strings the plating is not working for some reason.
- I am also assuming as you play, you are wearing off the nickel plating and eventually rubbing raw rusty steel on your soft frets.
I dont know for sure yet. I am just starting to look into this so I can save my $55 guitars frets
When I used to play cheap guitars I would change them when I noticed they were bent from touching the frets and would not stay in tune. And I had no fret issues back then