My 2013 did it a few times. 5th down to 4th once. Out and back in 5th once. Jumped out of 2nd into neutral once. Perty sure it was lazy shifts.
I have ADD, so it will probably happen more. Getting in the habit of taking off in 2nd. 1st is so low its not needed unless I'm taking off on a hill.
I ride a lot with Harley's and noticed my 2nd gear is much the same as their 1st. Its like a creeper gear. Good when pulling a trailer.
My 13 has 10k miles. Bought it at 8500k and did it right away. If it had done it on the test ride I would not have bought it.
It also makes a rattling noise while letting the clutch out.
Ride safe my friends