My phone still refuses to show any notes beyond April 8
That has got to be the fault of the browser, not of the phone itself. It's "gone bad" on that HHW page.
So which browser do you use? Try another one!

On my iPhone I use Safari for most things, but on every device I have (iPhone, iPad, MacBook), there are certain things it refuses to do right on certain sites. And that changes from time to time. In those cases I usually do better with Chrome. And there are others you can try as well.