Page Sections on custom pages do not format correctly

[pb-amy]

Description

Typically, when a new page is created at the network level and text is added, it creates a default textbox where text goes into. However, when users add a prebuilt page section (bordered, borderless, accent, etc.) to the page, the page content gets pushed down the page some distance. Example here:
https://open.ocolearnok.org/home/collaborate-with-us/

Steps to Reproduce

1. Create a custom page on Pages
2. Add a page section
3. Add text inside the page section

Expected behavior: The custom page section should remain where the default content normally appears

Actual behavior: The whole custom page section gets pushed past the header image.

[pb-amy]

https://pressbooks.zendesk.com/agent/tickets/3245