Creating an endpoint config overrides 'mac_address' value

When using the low level api, when using and endpoint_config as networking_config, it no longer uses the mac address declared in create_container. From my POV, both settings should be compatible, and the endpoint should not affect the mac_address assignation.

docker==4.2.2
docker-compose==1.26.2
dockerpty==0.4.1
pydocker==1.0.5
Python 2.7.17
Client: Docker Engine - Community
Version: 19.03.12
API version: 1.40
Go version: go1.13.10
Git commit: 48a66213fe
Built: Mon Jun 22 15:45:36 2020
OS/Arch: linux/amd64
Experimental: false

Server: Docker Engine - Community
Engine:
Version: 19.03.12
API version: 1.40 (minimum version 1.12)
Go version: go1.13.10
Git commit: 48a66213fe
Built: Mon Jun 22 15:44:07 2020
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: 1.2.13
GitCommit: 7ad184331fa3e55e52b890ea95e65ba581ae3429
runc:
Version: 1.0.0-rc10
GitCommit: dc9208a3303feef5b3839f4323d9beb36df0a9dd
docker-init:
Version: 0.18.0
GitCommit: fec3683

No repository file or test is identified in the issue. Reproduce the low-level API call using create_container with a mac_address and endpoint_config as networking_config, then trace how those settings are sent to Docker; done means the endpoint configuration no longer overrides the declared MAC address.