Modern News Pages and Highlight Content Web Part

You are not missing a step, the search on SP Online is still really unreliable, therefore I never rely on anything that is driven by search.

There have been times where items have shown up after days or weeks and some things just get missed.

1) Do a search for the page title, does it show up in the search results?

2) If it shows up in the search results query the search API to see if you can get the property like this 

https://orgname.sharepoint.com/sites/yoursite/_api/search/query?querytext='[[page title here remove brackets]]'&selectproperties='BlogVersionOWSCHCS'

3) If it doesn't show up in 1 or 2 log a bug with Microsoft