There's an anecdote about curl, but I'm not sure if there's enough in here to draw conclusions from. 20% of vulnerabilities have been made public, and many of those are marked as "withdrawn" or "duplicates". However, it's unclear whether the remaining 80% have not been made public because they're not fixed or real. In other words, this is analysis of survivors (public); not much can be said about those still under embargo.
And on top of that, it's a bit negative. How many millions of dollars is one perfect-10 scoring CVSS finding, total destruction style RCE, found in curl worth? Considering how many people use it.
The most likely explanation is that it isn't worth submitting a massive stack of bullshit to human review.
If they actually were sitting on a PR gold mine of vulnerabilities they wouldn't be throttled on review resources while artificially inflating/misreporting their numbers. They would be diverting resources to clear the review queue.
It's fake and it always was fake.
I'd expect the remaining 80% are delayed not because there's something statistically special about them, but from the massive workload thrown at humans in the loop.
Anthropic needs to teach their systems to propose a fix too. Detecting a coding problem and proposing a patch is what we should expect from a company with supposedly the best coding LLM.