Team site left navigation - checking on intended behaviour

Reaching out to the community and any Microsoft folk who might read this post. 

I need to clarify the intended behaviour of Team site left navigation where a page has been nested as a child of another.

When a person accesses the page by expanding the navigation, the page that the user has open is highlighted as the 'active page' - by way of subtle shading, a nice 'you are here' indicator. 

However, in my tenant, I have observed that if a user comes to the page via Search or from another page where a link has been placed, in say a Quick link, the left navigation does not open, so the user is not getting the contextual relationship of the page they are on + the 'you are here' signpost that the shaded navigation item is intended to convey.

I wanted to check if others have also observed this behaviour and know whether this is by design?  Or perhaps is there something wrong in my tenant? 

Grateful for any advice + ideas on how to resolve