Sorry I still say faulty TC or safety device in the valve. I am not familiar with the valve itself you have but I would see if it (the burner) could be jury rigged to one of the main burner valves. I will lay odds the issue goes away
It’s a single valve with a TC in the valve itself, no other safety valve, the valve attaches to the manifold just as the main burner valves. No, it hasn’t been tampered with.