Scenario: properly set up network that has https://mynetwork.com
Create new blog as site admin from scratch and activate an upfront theme (ie panino)
Set that newly created upfront blog as a blog template.
Sign up for a blog using that upfront blog template
Check the navigational elements...things are getting buggy via wether it main tains the use of pointing to wordpress object page or if it is instead switching it to a url (meaning if the page slug changes the navigational link wont be updated properly sitewide) In addition if its pointing to a url then https vs http is an issue as the links in view mode for admin mode are different causing issues for page redirects after clicks ruining clicks sliding anchor points.
This a a problem and I think i have figured out the use case, please test asap and confirm following those steps and relay to the developer asap.