Since the error is not so clear on why this is happening , this is where one needs to see whats the actual metadata for the object that is getting deployed.

There is an environment variable in the DX CLI named **SFDX_MDAPI_TEMP_DIR** you might want to set it to a temp metadata directory so that when sfdx push command runs you see the actual metadata thats being deployed.

Enable in MAC using `export SFDX_MDAPI_TEMP_DIR=/users/myName/myDXProject/metadata` .This assumes you have myDXProject as project folder and metadata as the temporary folder.

For Windows set it as an environment variable. E.g. in Powershell (expand the ... out with your actual path):

    PS C:\...\myDXProject\src> $env:SFDX_MDAPI_TEMP_DIR = 'C:\...\myDXProject\metadata'

Examining the metadata folder will tell whats going on here since it is weird.