Vibrating in steering wheel and hum

I have a new 25 yrs off road. About 2 weeks ago I noticed that around 30-40 mph when I left go of the gas the steering wheel starts to vibrate and there’s a humming noise. I took it in and they said there’s nothing wrong. I even went on a test drive with a tech and he felt and heard the hum, but they said they can’t recreate it. Had this happened to anyone else it’s driving me nuts