I think its related to this issue https://github.com/plone/Products.CMFPlone/issues/461.
originally in the UX hitlist.
The way it was done in plone has always been problematic I think that too much relies on the context and you have to be too aware if you are at the folder level, defaultpage folder level or page level.
Eventually I think the solution is to go all folderish content and have much more explicit actions.
I think we could switch to that now in preparation for folderish content and the user experience would be better.
e.g. add to folder, add to page, or an add dialog that lets you chose where you want to add something (see https://github.com/plone/Products.CMFPlone/issues/464)
or a single sharing dialog that lets you set at either the page or folder level.
or letting you edit the title and description of both the folder and the default page at the same time so its very clear they are separate and could also explain where they are used.
If this is done then you will no longer need to worry if you are in a folder or a page or a default page so this issue goes away I believe.
Lots of work though 