Policyfile: client.rb not updated when policy changes

Hello Chef Community!
While setting up an SAP node with policy files, we need to first bootstrap with a policy, and then change to another policy to finish the setup. We encountered a problem trying to do that.
To change the policy on a node, we use
"knife policy set <policy_name> <policy_group>"
After the command, we use
"knife node show " and it shows that the policy has really changed.
Nevertheless, on the next chef-client run. The policy is not updated. The same old policy is applied to the node, and we saw that the client.rb file /etc/chef/client.rb is not updated on the next chef-client run.
This is normal behaviour? We need -also- to change the file client.rb to effectivelly change the policy on the node, or the node should 'download' its new policy and apply once changed in the server?

Thanks in advance!


Sorry the environment is:
Linux Suse 15
Chef Client 14.13.11
Chef Server is on AWS Chef Opsworks:
Chef Automate Chef server 12.19.31/20190418172401