Anyone knows what this means? NG condition? RR 1mm means no longer enough?

Thanks for the advice. Just went and checked again, all four tyre thread is still comfortably above the TWI thread wear indicator, even without TWI its very obvious tyre tread still way above 1.6mm and rubber still in good condition.

Which is why I asked here, idk how workshop got the 1 mm and NG thing. That said already planning on my next tyre, michellin XM2+ or continential CC6.