Clunking Over Bumps that move the truck side to side

Hi guys, I have an 06 Off-Road. It has a 2.5" suspension lift, no spacers, and for a few weeks now I've been hearing this noise that sounds like it's almost coming from behind the dash. Like behind the radio or near the glove box. It is only noticeable at slow speeds over deep bumps that will rock the truck side to side. Like crossing into someone's driveway, or a pothole that just one wheel hits. The truck does have a Sony XAV head unit with the crux steering wheel button adapter box. Think it could be as simple as that moving around in the dash? I did pry on the wheels tonight, no play had an alignment about 2 months ago, they claimed everything was tight, I drive mostly smooth roads, so I only hear this noise rarely. It's really on bumps that just move the truck side to side, like culverts that are cracking through the road and only at low speed. I have checked the joint under the dash and it appears to be tight. Truck drives awesome other than that, stock upper and lower control arms, goes straight and smooth at 75. Any insight would be appreciated. Leaving for a good-sized trip in a week and thought this should be addressed.

 

I also experience this, and I'm planning on installing new sway bay bushings in the near future. I haven't had a good look down there yet but it sounds like the bushings are worn; cheap parts either way.

 

The head unit won't make the truck "rock .... side to side".

Take a close look at your suspension. Springs, sway bars, shocks.

The alignment guys probably only checked the components that affect alignment.

What is the mileage? Service history on the suspension?