Paint wearing off in the antenna band

I purchased an iPhone 6s in August in one of the reliance stores in India.

In September,I noticed a few white spots near the charging port.I never dropped my phone and used it with a spigen rubber hard case from day 1.I took it to the service center,and my phone was exchanged.Now,the white strip(antenna band) has 2 spots(as the paint has stripped off) and background rose gold color is visible.Is it some serious issue with the hardware?Will it lead to any connectivity problems?

Thanks in advance.