of course you didn’t. on youtube ads are not served from different domains. have you ever heard about pihole not being able to block youtube ads? that’s why. every ad is literally a video uploaded to youtube, it is even possible to watch them as videos, with their own video page.
So it's not a privacy issue, it's an ad issue. Which doesn't show, it's blocked.
What does uBO do different here?
or when ads start reappearing. the needs to wait for the next addon update, which may take multiple days.
Just FYI - that only happens to me on YouTube every once in a while. Like, three times this year for a day or two.