I had the same issue with a new G17 I bought in May. I took it to a local amorer with no improvement and sent it to Glock. It came back worse. I sent it back and requested a new gun. When the new gun showed up at my local gun shop, I asked if they would exchange it for a new M&P 9. They agreed and I have been totally happy with the M&P (after an Apex DCAEK installation).
The BTF does not show up on every gun, but it happens far more often than one would expect.