Mouse cursor disappears after switching to another window in Borderless Window

[Redthirst]

Your system information

• System information from steam (Steam -> Help -> System Information) in a gist:
• Have you checked for system updates?: [Yes]
• Are you using the latest stable video driver available for your system? [Yes]
• Have you verified the game files?: [Yes]

Please describe your issue in as much detail as possible:

After swapping to another window in Borderless Window mode, my mouse cursor in Dota disappeared.

• It's still visible in windowed mode, but hidden in Borderless or Fullscreen.
• Restarting the game/verifying files/disabling and enabling Vulkan DLC doesn't fix it.
• Using alternate cursor packs doesn't work.
• Cursor works fine in DX11.
• If Dota window isn't in focus in Borderless mode, then cursor is visible whenever I hover over Dota window. Focusing Dota instantly hides the cursor.
• It got randomly fixed today, but restarting the game broke it again. For now, I'm back to using DX11 since lack of mouse cursor makes the game unplayable.
• I haven't found a reliable way of fixing it.

Steps for reproducing this issue:

1. Use Dota 2 with Vulkan in Borderless Windowed mode.
2. Switch to another window and then back to Dota.
3. The game cursor disappears. I managed to play a full game before it happened, so it doesn't seem to be reliable. The window I switched to when it broke was on my second monitor.