According to Intel, the CET NOPs are not treated as NOPs by older processors. Depending on what “older” means in this context, we may have to disable it for i686 builds in Fedora.
The x86 SIG did not find any issues with the change, so we left CET enabled for the mass rebuild: https://lists.fedoraproject.org/archives/list/x86@lists.fedoraproject.org/thread/XP6FWTHQS5PEFOLYIPTJUOMDEVMS6M5S/