System Information
Operating system: Linux-5.11.0-7614-generic-x86_64-with-glibc2.32 64 Bits
Graphics card: Quadro RTX 6000/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.73.01

Blender Version
Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-08-30 15:04, hash: rBe8684eff301d
Worked: 3.0.0 Alpha, branch: master, commit date: 2021-08-24 13:15, hash: rB7aff40f410f4
Caused by rB038f9b7f4a0e: Render: Lazily allocate render passes pixels storage

Short description of error
When rendering a bordered region (both Eevee and Cycles), after successfully rendering the image it simply disappears.
(There are also tiny render tile borders hanging out after the rendering process as visible in the video. Unsure if that is related...)

Note: this does not happen when Crop to Render Region is enabled, nor when the selected region is the full camera frame

Exact steps for others to reproduce the error
From standard startup:

• Start from camera view
• Press ctrl+b and select a render region that is not the whole camera frame
• F12