I think the 3.3 error has nothing to do with the IAB vendor list and the recommendation from Quantcast.

Namely, I use Quantcast for one website and I saw the same recommendation, which did not disappear even after I selected everything. Just ignore.

3.3 error means that the TC string last updated date was more than 13 months ago. As far as I know, nothing needs to be done here and it will fix itself after a certain time.

You can also read explanation about errors on Quantcast:
[help.quantcast.com...] IAB-TCF-v2-Error-Codes-Guidance

I've had this message for weeks now. No idea how to get rid of it. 3.3 errors suggest that consent needs to be reobtained.

I've required updated consent from users twice now, but that does nothing. The message in Adsense persists.

It's frustrating because the warning in the Adsense dashboard suggests that EU revenue may be throttled due to the GDPR issue. But there's no indication of what to do about it,

Hello Senechal and welcome to WebmasterWorld [webmasterworld.com]

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