[Affected versions]: - Firefox 57.0a1 Build ID 20170910220126 [Affected Platforms]: - All Windows - All Mac - All Linux [Prerequisites]: - browser.newtabpage.activity-stream.enabled is set to true in about:config on a clean new profile. [Steps to reproduce]: 1. Start the browser with the profile from prerequisites. 2. Navigate to 12 different websites. 3. Open a New Tab. 4. Restart the browser with the console command. 5. Observe the Highlights section. 6. Refresh and observe the Highlights section. [Expected results]: - Step 5 & 6: The same Highlights cards are displayed. [Actual results]: - Step 5: A few Highlights cards are displayed. - Step 6: Some Highlights cards disappear. [Notes]: - The issue is also reproducible if you close and reopen the browser as long as you have the "When Nightly starts: Show my windows and tabs from last time" option selected in about:config. - The issue becomes more apparent if Activity Stream is the default home page. - Attached a screen recording of the issue.

Fixed by https://github.com/mozilla/activity-stream/pull/3451 to be uplifted via bug 1399607.

The Highlights cards that you have before a refresh, remain the same after you refresh the page. Verified as fixed using latest Nightly 57.0a1 Build ID 20170917220255, on Windows 10 x64 and Mac 10.12.