I assumed the parameter --verify essentially runs solve-field with a known RA, Dec and plate scale and see if it can improve the header when matching the field to the indices at hand. This should make it pretty quick.
In my current case, --verify attempts to verify using all indices ranging from 10% to 100% of the field size but gets zero solutions, which triggers a regular all-sky blind solve. Moreover, we are using a specific CRPIX definition not at the image center, but the result is a file with a seemingly arbitrary CRPIX location - apparently, the blind solve that is executed after --verify fails ignores any existing WCS definition.
I am having trouble to understand why our files can't be verified. The files at hand have a WCS header based on a simple TAN / gnomic projection without SIP coefficients, and the same keyword definitions as solve-field would add. The files have been verified by other means, i.e. they produce correct results in Aladin.
What am I missing, or do I misunderstand --verify completely?