I had the exact same thing happen on my stovetop not long after I bought my TT.
The burner "head" is secured to the support bracket with a small machine screw. It was loose and vibrated out while going down the road.
Lift the top of the range. There's a spring clip at the center front. A stiff putty knife inserted, pushed in hard, and prying up will allow the top to swing up.
Remove the bracket which is held in place with a single phillips head screw.
Look around the area around the burners for the missing screw. Mine was under the igniter assy but it could be anywhere and it's hard to fall out of this "pan" that's designed to catch "boil overs".
Re attach the burner to bracket, reinstall bracket, and before tightening make sure burner tube is snug over the gas jet housing.
If you can't find the screw check out a hardware store like ACE, etc. They usually have trays of these small screws and you only have to buy one, of the right length (unlike Home Depot that forces you to buy packages of 3, 5, 6, etc.)
Hope you have the same luck as I had and find the screw. While you're at it, remove the other burners at the bracket, turn over, and tighten that same little screw. Heating and Cooling of the burner head's metal can cause the screw to loosen over time. Using thread sealer is ineffective due to the heat.
"A wise man can change his mind. A fool never will."
"Sometimes you're the dog, sometimes you're the tree"
2018 Flagstaff Micro Lite 25BDS
2004 Nissan Titan