left airpod sensor (facing ear canal) sticking out

I have a non-technical question, sorry for being a perfectionist and picking bones out of eggshell.

When I swipe my finger over the proximity sensor (facing ear canal) on my left airpods, it feels that the sensor is bulging and I can definitely feel it sticking out. Whilst on my right airpod, when I swipe my finger over the sensor, everything feels smooth, and continuous. Secondly, when I look horizontally and compare both airpods side by side. I can see the proximity sensor on the left airpod is not uniform with the airpod casing.

Is this a common product problem, or is it just happening on my pair of airpods specifically?

Above is left earpod (notice the black proximity sensor sticking out)

Above is right airpod

Thank you for the help!!