The problematic documentation is 8.2.4.2. Creating Open vSwitch (OVS) bonds.

And the below example is mentioned in the above documentation.

environment_parameters:
  BondInterfaceOvsOptions: "bond_mode=active_backup" 

But as far as I know there is no parameter, environment_parameters.

I guess the parameter should be parameter_defaults instead of  environment_parameters like below.

parameter_defaults:
  BondInterfaceOvsOptions: "bond_mode=active_backup"