iOS extension-manifest-v3 loading after website is restored from previous session.

[gradogirl]

Ads are not fully block on cold start until website is refreshed in iOS Safari.

Tested on youtube.com (video); windsorstar.com (newspaper).

Looks like Ghostery is loaded after website is restored from previous session.

iOS 17.4.1.

[chrmod]

Thank you for report.

It is a race condition, extension is not able to start before the page starts loading and this is why some ads are able to pass by the ad-blocker. This happens only for so called Cosmetic Filters, the ones that hide page elements or inject special scripts. Network requests should always be blocked.
I'm afraid there is nothing we can do about it, this is just a consequence of Safari architecture.

@GRadziejewski can you please test other iOS adblockers to see if they are able to bypass this problem?

[gradogirl]

1blocker is able to bypass this problem consistently. Tested on iPhone 14 running iOS 17.4.1.

Is this a way for the extension to suspend network activity (deactivate prefetch, dns-prefetch, preconnect and/or fire blockable webRequest Events) until Ghostery is loaded? This race condition probably exists in Chrome as well. Virtually every browser defaults out of the box with prefetch enabled, privacy implications ignored.

https://developer.mozilla.org/en-US/docs/Glossary/Prefetch