Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: GeForce GTX 1650/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 441.66
Broken: version: 2.81 (sub 16), branch: master, commit date: 2019-11-20 14:27, hash: rB26bd5ebd42e3
Short description of error
Blender doesn't save previews that look as the eevee (or cycles) render when using a camera.
Exact steps for others to reproduce the error
Use a file with a camera, save while rendered mode is on, and it will look like workbench mode.
Delete the camera, it will save as the mode is displayed and will do as rendered if that's what you have.