[TimPC]

Anecdotes are not data. Even in plural form. We can witness isolated instances of what seems to be a phenomenon without it actually being part of a phenomenon. Other posters have already established that some experts can overestimate their expertise as well. The study mentioned by the original post and in my comment seems to suggest that the overestimation bias is prevalent across a wide range of cohorts of expertise. Senior students are just as likely to overestimate their talents as freshmen for instance. This effect likely extrapolates to experts as well it's just hard to get good data.

No DK doesn't say no bluster, no proclamations or no artificial assertions of expertise. It doesn't even say that the overestimates are just as prevalent among experts as laypeople. All it says is as near as we can tell the effect size of the overestimation is the statistical autocorrelation and our best efforts to produce the same effect without relying on the autocorrelation have failed.

I think there are a lot of ways to accept the anecdotes you mentioned occur that need much weaker assertions than DK as a psychological phenomenon and would hesitate to jump to DK based on that information.