F39 mass rebuild failed for package libspf2 and the error points to API documentation files generated by Doxygen not being the same when generated on different architectures:
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BuildError: The following noarch package built differently on different architectures: libspf2-apidocs-1.2.11-8.20210922git4915c308.fc39.noarch.rpm
rpmdiff output was:
added       /usr/share/doc/libspf2-apidocs/html/a00171.map
added       /usr/share/doc/libspf2-apidocs/html/a00171.md5
added       /usr/share/doc/libspf2-apidocs/html/a00171.png
removed     /usr/share/doc/libspf2-apidocs/html/a00174.map
removed     /usr/share/doc/libspf2-apidocs/html/a00174.md5
removed     /usr/share/doc/libspf2-apidocs/html/a00174.png
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I think we've seen similar problems with Doxygen in the past.

Reproducible: Always

Steps to Reproduce:
1. Run build of libspf2 for F39 in koji.
Actual Results:  
Different documentation files produced on different architectures.

Expected Results:  
Checksums of files should be identical.