RPCS3 Minimizing or Switching to Windowed Mode When Pressing Start (Xbox Elite V2)

Hi everyone,
I'm experiencing a weird issue when playing Demon’s Souls on RPCS3. Every time my friend presses Start on his Xbox Elite V2 controller, the emulator switches from fullscreen to windowed mode (or minimizes). The game runs smoothly otherwise, and no other buttons cause this issue.
Setup Details:

• Game: Demon’s Souls (BLUS or BLES version, tried both)
  
• RPCS3 Version: (latest stable build)
  
• OS: Windows 10 / 11
  
• Controller: Xbox Elite V2 (XInput mode)
  
• Graphics API: Vulkan / OpenGL (tried both)
  

Things We've Tried:
✅ Checked RPCS3 keyboard shortcuts (Start is not mapped to anything weird).
✅ Set the game to start in fullscreen / borderless mode.
✅ Updated controller firmware & GPU drivers.
✅ Ran RPCS3 as Administrator.
Issue Still Happens When:

• Using another controller (also an Xbox one).
  
• Using another RPCS3 build.
  
• Running the game in different display modes (Fullscreen, Borderless, Windowed).
  

Does anyone know what could be causing this or how to fix it? Any help would be greatly appreciated!

SOLUTION: STEAM MUST NOT BE RUNNING