We're aware that YouTube has been intermittently testing strategies to show either ads or their anti-adblocking wall. If you are seeing a brief display of an add, these are related to our efforts to stop adds on YouTube. However, in some cases we've found that your settings might have changed which is why ads are suddenly appearing. Please try the following steps:
1 - Signing out of your YouTube account
2 - Make sure you haven't added YouTube to your allowlisted websites
For more information, don't hesitate to contact us on support@adblockplus.org