macOS Catalina creates "Relocated Items" on every update
I also experienced this problem over several Catalina and Big Sur updates.
I too had a /p link defined in /etc/synthetic.conf
I too noticed the rivate misspelling.

So before updating to macOS 11.4 today, I rebooted in recovery mode and removed my synthetic.conf. The update then installed normally, without blowing away my /var and /etc directories and without running the new installation setup. I conclude that having a /p link does cause this problem.