As part of the LDM-503-RSPa test campaign being carried out, we discovered that Rubin images downloaded from the Portal via the "diskette" button in the image toolbar have "error"-level errors flagged by "fitsverify", apparently relating to an incomplete transformation of the three image extensions from compressed-image extensions (stored as BINTABLE) to uncompressed ordinary image extensions:
The "TFIELDS" header is still present in the image extensions, but this header is only for use in ASCII or binary table extensions.
It is possible that a newer version of nom.tam.fits may correct this, or perhaps Firefly will have to tackle this directly.
https://github.com/nom-tam-fits/nom-tam-fits/issues/105 alludes to what seems to be this problem. (However, note that "TTYPE1", mentioned in the issue, is not in the Firefly output file's image extensions, unlike "TFIELDS".)
fitsverify output from "direct" download and "via-firefly" download is attached.