My mouse sensitivity randomly changes while playing Fortnite

To troubleshoot this issue, you can try disabling the enhanced pointer precision setting on your mouse, following these steps from Microsoft: Change mouse settings (เปิดในแท็บใหม่)

Enhanced pointer precision changes the sensitivity of your mouse depending on how fast or slowly you move it. This leads to your mouse sensitivity changing while in-game, making it difficult to rely on muscle memory in shooting games.