After Agent update to build 25851 (part of Acronis Cyber Cloud 20.11 release) Acronis Cyber Protection monitor automatically pops up in tray after each login to the machine:
Issue in the product.
This issue is fixed Acronis Cyber Cloud 20.12 Build 26077. Please update Agent to the latest build.
As a workaround for earlier builds, click anywhere on the screen outside the window to minimize it. You can also disable the Cyber Protection Monitor temporarily: see How to disable Cyber Protection Monitor