I heard back from Adsense support about my significant rise in clawbacks over the past few months (25%, 41%, and then 56% for June).
For May's clawback they said that my users were accidentally clicking on my ad units, and they advised adding extra spacing and the word "Advertisements" above the ads, which I did.
After June's clawback was even higher, Adsense support blamed suspicious IP addresses, and then advised assigning a unique ID to each user, and cross-checking that with my website access logs.
I've been with Adsense for over 15 years, and earned high six figures. I've never had nearly such large clawbacks as since COVID started.
This coincides with a bizarre experience I had with Google Ads. A Google public relations person contacted me to recruit me into a managed Google Ads program for one of my sites, where they would create and handle my ads. We had multiple phone conversations over hours, and agreed on a daily budget for my site that they would use in Google Ads. Then we had a conference call with a tech guy, and then a third call with someone who walked me through the implementation.
Then I received an automated message about how my site was rejected from Google Ads for malware. I removed various scripts, personally examined javascript on my site, and couldn't find any malware (Google Search Console malware checks never indicated any malware on my site). I appealed the malware check, and a Google tech support person responded with a list of the "malware" urls on my site. The list didn't include any malware; there were links to my homepage, images (hosted on S3), and other urls that couldn't be malware. The PR person handling this and the tech guy were both confused about what was happening. I found a post on reddit from someone describing the exact same weird automated malware rejection issue. I appealed the malware check again, but this time my site was approved.
When the Google Ads campaign ran, it went at twice our agreed-upon budget for two days, until I paused it after just under 10,000 impressions. The campaign had no conversions, and an average CPC of $14.63!
The whole experience seemed like a weird failure of automation. Combined with the suspicious clawbacks, I decided to remove all Adsense from my sites. Prior to this, they've always been reliable over the years. Obviously something strange is happening at Google, and it's too stressful now to deal with mystery clawbacks and their awful support.
