The issue is different:
both x86_64 and ppc64le builds python-ioprocess package so a newer python-ioprocess may come from ppc64le build not corresponding to an exact nvr on x86_64.
Solution may be to chance the ioprocess build to drop the timestamp or make the ioprocess build a matrix job building from the same src.rpm.
Another solution may be relax the nvr requirements in the python-ioprocess package to not require the exact nvr but only the same version.
Another solution may be competely separate x86_64 and ppc64le repos.