The "Done" banner typically indicates that you're using an in-app browser. You've invoked an html page, maybe through http. And if that page has javascript or other complicated web code, this might slow the load time for the page.
I'd be more inclined to author each article as a single index.html page in its own folder. Any CSS, images, js, etc. that the page calls would also be in that one folder. Then package the folder and use this as your article content.
This way, you'd have automatic swipe navigation to the previous/next article, DPS will preload neighboring articles to speed up the load experience, and each article could be in the collection browse page.
HTH