I can confirm what @sgei is reporting but on my cubietruck with the latest armbian buster release. See my screenshot:
top shows some kworker thread "events_freezable_power_" every few seconds with 10% load. Seems to be related somehow. At least this leads to the CPU being almost continually clocking @960MHz.
I found this one recently: https://superuser.com/questions/1515001/debian-10-buster-on-cubietruck-with-bug-in-sun4i-drm-hdmi
Maybe it helps? I will have to test this in the long run.
Is there any news on this kworker issue? Actually, I'm running armbian 5.90 with 4.19.57 kernel an the problem persists. Before, I was running dev-kernel 5.1 which didn't fix the issue either.