Comment # 1 on bug 1170232 from Michal Suchanek

That's correct behavior.
kernel-default-5.6.4-1.1.x86_64 and kernel-default-5.6.4-1.2.x86_64 are
different build of the same kernel sources. You can only have one of them
installed.

The obsoletes listed above do not cause problems. As noted in the RH bug it
only happens 'sometimes' - that is when there are multiple rebuilds of the same
kernel.