After applying the 8.2.1 update, the metadata (CPU usage, CPU Load, and number of accounts) and disk or bandwidth use for Plesk servers and hosting accounts may not be reported accurately. This affects configurations with multiple Plesk servers.

A hotfix has been created for 8.2.1 only to correct this behaviour:

https://whmcs.community/files/file/169-module-7660-plesk-server-usage-and-meta-data/