Oy vey: there is an error, but how to find it?

Why does it run
image
when apparently the latest release is 0.27.4?

It isn’t clear to me whether the Documenter code has an error, or if it somehow gets tripped up by my own code? Anyone knows?

Might have been outdated project files. After update the error went away. (It runs 0.27.4 now.)