In a report from Chrome Unboxed (via Android Police) who first discovered the bug, it seems that Chrome OS is consuming quite a bit of CPU power. What could be causing this high CPU usage? Here’s where it gets a bit ironic: it only seems to consume a lot of CPU power when the task manager is open.
It is unclear as to what might be the cause behind this very ironic bug, but it doesn’t seem to be affecting all users, so your mileage may vary. It also doesn’t seem to be device-specific and according to reports, appears to have affected a variety of Chrome OS devices like the Pixelbook, Pixel Slate, Samsung Chromebook Pro and Plus, and so on.
Some users are experiencing pretty high CPU usage between 50% to 100%, resulting in a very noticeable lag when using their devices. It has been reported that disabling Android app support helps, so you can try that if you’re experiencing this problem. Google is currently looking into the issue so hopefully, we’ll have a fix soon.