Power button loose after refitting and not clicking

Hi, maybe someone can advise on whether there is a special technique for installing the power button after removal, or if there's a part missing.

Metal bracket fits properly back in place behind button, and orange disc popper attached to it and clicking. Silver button installed in iPhone as per guides, but it seems there's a gap between silver button and orange disc on bracket, so switch is loose and when pressed it does not activate the disc switch and click.

This is the 2nd time I've had this happen. Is there a spacer between orange switch on flex, and the silver button which drops off or something?

A thin rubber strip with a cutout running its length (about 5 or 6mm long) fell out and I can't see where it came from, and a rectangular rubber pad which I think came from the speaker/charging dock end, but nothing else I saw.