Front end wobble/bouncing after hitting bumps - out of control

1. I bought the truck used 1 yr ago and have put on 10k miles. The wobble/bouncing has occurred 3 times. Truck has aftermarket 18" rims w/ aggressive wider tire and a 3" body (leveling) lift in the rear only. In these 10k miles, both ball joints, tie rods, and bearings have been replaced and a steering stabilizer bar added.
2. It happened twice at 70mph after hitting a pothole. The front end/steering wheel was out of control jerking back and forth fast. Regained control around 30mph. 3rd time was hauling a trailer at 55mph hit a few small bumps in succession, but the front end started bouncing higher and higher after the road smoothed out. No steering wheel wobble this time - more of a fast bounce, but maybe the trailer caused that (3600lb bumper pull). I think the trailer brakes slowed us because wheels weren't on the ground. Couldn't regain control until 20mph and off the road.
Love our mechanics. We've been using them for years for multiple vehicles, but they're out of ideas other than just start changing parts. Shocks seem fine. I am ready to go back to stock on the rims/tires. I have the money, but the problem is so random. I don't want to die or kill someone and have just been lucky w/ no other cars around so far.