Auto-generated fields cannot be excluded and applied in kubernetes version 1.19.7 and before. In order to workaround this problem, upgrade kubernetes version 1.19.9.
For ex., pick a config map and get the yaml
kubectl get configmap -o yaml.
Try modifiying the auto-generated fields and apply, you will see the error. Although modifying is not allowed, deletion of the auto-generated fields seems to work in 1.19.7.
Solution/Workaround: Upgrade to kubernetes 1.19.9