I have a question about the Lagrange duality problem

What form of non-convex QCQP problem satisfies strong duality, I saw that the book on convex optimization mentions that the optimization problem of minimizing non-convex quadratic functions in the unit sphere is strongly dual, but the argument in the book feels incomplete, I want to know if there is only one form of non-convex QCQP problem that is strongly dual? Or are there other forms of QCQP, such as: the objective function is convex and constrained non-convex.

This does not really pertain to CVX or convex optimization. So it is off-topic here.Perhaps post at https://or.stackexchange.com/ or https://math.stackexchange.com/