Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 419.35
Broken: version: 2.80 (sub 74), branch: blender2.7, commit date: 2019-06-02 21:33, hash: rB19dcb22a885d
Short description of error
The combined pass is allways written to file, even though Combined is unchecked in the View Layer Passes Data tab.
Exact steps for others to reproduce the error
Open the attached blend file.
As you see Combined is unchecked in the View Layer Passes Data tab.
Hit Ctrl+F12 to render the Animation. The multilayer-exr is stored in the tmp folder.
See the multilayer-exr layers, the combined pass is stored within.
So the combined checkbox in the View Layer Passes Data tab isn´t doing anything if you check or uncheck it.