I have a TS-453Be
(same issue / reported by etakpte)
High CPU load when Idle.
After the update, the NAS (even after reboot) frequently showed idle CPU use of 65% frequently jumping to 100%.
I am also using Virtualization station. But to assess regular idle CPU, I shut down all VMs and stopped all non-QNAP apps (Plex). No Change still very high idle CPU use.