3D Viewport can not keep framed selection as pivot point, please please help me!

This is so annoying, its happened in a few of my scenes and I don’t know why, maybe its simple! and ive hit a keybind that unlocks it or something. Basically the camera wont pivot around my framed selection and it appears to constantly pivot around the centre of the camera view if that makees sense?

All I want is for it to pivot it around my framed selection as it should do and normally does!

heres a video to make it clearer.

please please please can someone spare me from my misery

Try " numpad . " (or view menu - frame selected)

“normal” behaviour for Blender is to pivot the viewport on the viewport camera
Edit
there is a preference setting under the preferences “navigation” tab if you want Blender to “orbit around selection”