both my front rotors are grooved only 14,000 miles on it. brought it to vw ,was told pebbles or road grit got between pad and rotor. vw wanted to replace rotors for $ 500. have 1 more year on lease
A small amount of grooves on rotors is not uncommon. But no one could tell over the internet if unsafe to drive. If rotors are replaced might as well get new pads, old pads would be grooved too.
You might get an opinion from an independent mechanic since wear items are not normally covered warranty.