I've added this to the 'feedback' section of the forum. I have always hated this 'feature' and not sure why it was implemented.
https://forums.autodesk.com/t5/3ds-max-ideas/prevent-isolate-selection-from-changing-the-camera-view...
"Going into 'isolation' mode by pressing ALT&Q, the camera resets to some portion of the scene that is unrequired. This results in loss of orientation while modelling and needs the user to always reset the default camera view - exitting from isolation mode then moves the viewport to another position, and again requires the user to reset the viewport camera.
There is now rhyme or reason why isolation mode should do this. The viewport camera should never be moved unless the user wants it to."
