This is an attempt at explanation from a beginner. Take this observation with a pinch of salt. It’s possible that I am following the wrong track.
If I understand this correctly, there are some problems with mounting “proc” onto /usr/lib64/lxc/rootfs/proc which is essential for the further startup process.Without it the process fails.
The question is why can’t “proc” be mounted onto /usr/lib64/lxc/rootfs/proc?
Maybe the thing called “proc” that should be mounted onto /usr/lib64/lxc/rootfs/proc is corrupt?