Hi Anna Fitzgerald 

Typically the options on the Ribbon are in context of the view you happen to be in when working in Studio.

Example:

When in Editor view you see Review / Advanced, with the Home tab showing features that relate to the Editor view 

Yet when you are in project view, you dont see Review/Advanced and the Home tab show features that relate to project management such as "New Project"

Therefore its not strange you pick up on differences but it is dependent on what views you are comparing against.

That said, if you are comparing the same two views in Studio like the Home Tab for example... then it could be one of your instances has a custom ribbon as that is a feature that we support

Looking forward to your clarification on what views are you comparing against and what you notice when looking at the custom Ribbon (which is also based on contextual view in Studio)
First image being that of the Home View with the second below being of the Editor View

I hope this helps

Lyds

Hi Lyds,

Thank you so much for your detailed response. Yes, I can see that in the Editer view, I see all the tabs. Thank you again for your help.

Have a good day, Anna