The newest version of Microsoft Edge has been officially rolling out to users on Windows 10 1803 or later since June 3, and if you’ve been experiencing strange startup behavior with the new version do not be concerned. Microsoft is aware of and currently investigating an issue were the new browser starts up even if it’s set not to do so. Microsoft does not know what is causing the issue yet, but they are hoping to have it quickly resolved by examining diagnostic data shared by users. For more information, feel free to check out the link below.

Source: Microsoft investigating Edge self-launch on Windows startup