Ads don't get blocked on Youtube tabs that Firefox restores

[sim642]

Describe the issue

When Firefox crashes and is restarted, it offers to restore the previous tabs. When a restored tab is a Youtube video tab, the tab loads and all the ads are not blocked. Refreshing the page or visiting any Youtube videos at any later time properly has them blocked.

One or more specific URLs where the issue occurs

https://www.youtube.com/watch?v=ehV_I7LEXbA

Steps for anyone to reproduce the issue

1. Have Firefox open with active Youtube video tab
2. Crash or kill Firefox
3. Restart Firefox and restore the tabs
4. Observe that the Youtube video tab which opens has ads which are normally blocked (e.g. the banner on above the right hand side suggested videos list)
5. Refresh the page to see that they actually get blocked properly if the page is loaded not as part of tab restore

Your settings

• OS/version: Xubuntu 16.04
• Browser/version: Firefox 56.0
• uBlock Origin version: uBlock Origin 1.14.18

Your filter lists

Default filter lists + EST

[gorhill]

Duplicate of #1327.