Puzzling "Warning: duplicate docs found"

[NicholasWMRitchie]

I am so puzzled about why I can't eliminate a "Warning: duplicate docs found" error message.
I'm documenting a structure Spectrum. I've only documented it once. Yet when I attempt to

"""@docs
Spectrum
"""

I get the mentioned error message. However in @autodocs, the documentation for Spectrum shows up just fine.
Even weirder, I remove the structure documentation and I continue to get the error message and the just deleted documentation continues to show up in the @autodocs. It is as though there is a cache that is holding on to the deleted documentation.
Is there a secret cache somewhere that has been corrupted?

[KristofferC]

However in @autodocs, the documentation for Spectrum shows up just fine.

Isn't that the issue? That you have it documented with @autodocs and @docs thereby having duplicate docs for Spectrum?

This might be a dup of #1079.

[NicholasWMRitchie]

I'm still confused because 1) it would seem that all the other @docs should also report as "duplicated" but only this one does (or can method docs be repeated but structure docs not?); 2) I remove @autodocs and I still get the error (I only explicitly include @docs Spectrum once); and 3) (the weirdest part) this doesn't explain why I can delete the documentation from the source code and it still gets included by @autodocs.

[KristofferC]

Do you have a separate manifest used for the docs?

[NicholasWMRitchie]

I guess that even when a page isn't included in the pages argument to makedocs(...) it is still being processed. This explains 2).

[NicholasWMRitchie]

I have a "Project.toml" but not a "Manifest.toml"

[NicholasWMRitchie]

I'll close this because I don't know there is really a problem here and not just a misunderstanding on my part.