This is linux path "/usr/local/psa/var/certificates", my problem reproduced on IIS (Windows Server 2016).
Ok maybe it's true:
During the process, Plesk has to include situations, where the certificate is ONLY valid for domain.com and not for domain.ru, so the only accepted policy is to remove the previous installed certificate, when you delete/rename the domain.
Main question, why delete certificate from Default Web Site, which is not domain.com or domain.ru, i.e. hosting.example.com?