Update:
Something is interfering with the downloads. The MD5 hash I get using FDM from Fosshub differs from the MD5 hash I got when using FDM to download from the Default Calibre Download page.
The MD5 hash I got using FDM from Fosshub is bc44849e4e352978ea7eb3fdba5d8bf4
The MD5 hash I got using FDM from calibre is d2df5871ebd968db9a9ccb21a7b29963
Another download using FDM generates 6803f0a78e7abbd386b2af015070ce1f.
Hmmm.
What gives?
Even downloading the file with a different extension, and then renaming doesn't work (and generates a different hash).
@gdp: I tried your suggestion downloading from Private mode. That gives me a hash of: d95b33fa0a3b0613a53f054932a2c844.
WTF?