Quote:The Action Center, which is the place to go for checking notifications or accessing quick actions, sometimes opens on the left side of the screen and not on the right as it’s supposed to. This behavior takes place for just a second before it shows up correctly on the right of the desktop.

Microsoft says that this behavior has been resolved in Windows 10 build 18267 available for participants in the Windows Insider program.
“We fixed an issue where the Action Center might suddenly appear on the opposite side of the screen before appearing on the correct side,” the release notes read.

Additionally, there’s also a fix for a second Action Center problem related to notifications displayed on Windows 10 PCs.
“We fixed an issue resulting in the Action Center icon sometimes showing a number of unread notifications, however when you opened Action Center it would be blank,” Microsoft says.