Unity Editor behaving differently than a build when using Network High Level API

While testing a networked game using Unity's high-level API, the build version behaves differently than the game in the Editor.

The game running in the Editor behaves correctly and only controls the local player with the game controller whether the Editor is the Host or the Client. However, the game running on the build will control both players whether it is the Host or the Client. I am very confused at what is causing this problem since it seems to be dependent on how I am running the game, not whether the game is a Host or Client.

Any help would be greatly appreciated.

Thanks

UPDATE: I just ran two builds simultaneously, and they both are working correctly (only controlling local player whether Client or Host). The issue seems to be with a connection between the Editor and a build. Now I am very confused.

UPDATE 2: While running two separate builds and the Editor simultaneously, it appears that each game running on a build will also control the Editor's local player no matter whether they are Host or Client. Could the problem be with my controller being connected to the Editor even while I'm clicked in the build and the Editor is running in the background?

UPDATE 3: The Editor takes controller input no matter what window is in the foreground. Is there a way to disable this feature?