/usr/lib64/glibc-hwcaps/power9/libc.so.6 and the other sonames are symbolic links. ldconfig does not perform symbolic link processing for glibc-hwcaps subdirectories, so the cache entry for libc.so.6 points towards /usr/lib64/glibc-hwcaps/power9/libc-2.28.so instead of /usr/lib64/glibc-hwcaps/power9/libc.so.6. For now, this is just cosmetic. If we do not change the target of the /usr/lib64/glibc-hwcaps/power9/libc.so.6 symbolic link, then I do not think the difference matters.