If you alt+tab Might Magic and Magic: Heroes VI using Proton 11.0 and comes back to the game later, it's rendered as a small tile on the top left corner (see image below). The problem doesn't happen with Wine D3D. Let me know if any more information is required.

Software information

• Name: Might and Magic Heroes VI
• Settings: Maxed out at 1440p

System information

• GPU: RX 6700 XT
• Driver: Mesa 26.0.6
• Wine version: Proton 11.0-2 (RC)
• DXVK version: Proton's 11 branch
• DE: Plasma 6.6.5 (wayland/x11)

Apitrace file(s)

• Put a link here

Log files

Please attach Proton or Wine logs as a text file:

• Proton logs: steam-48220.tar.gz