I come to you heartbroken and defeated

[Dave Weaver]

If the knobs won't pop back into place, there's an issue with the manifold internals.
You'd probably have to replace the manifold assembly, as I know Weber doesn't recommend trying to take the manifold apart to service it.

 

[MWindom]

The manifold is also new. The grill parts are all new. The knob stems pop back up but not when the knobs are on it.