Thats what it supposed to do.
You can see this in the script or check here:
Performing Maintenance on DAG Members
Runs Suspend-MailboxDatabaseCopy with the ActivationOnly parameter to suspend each database copy hosted on the DAG member for activation.
Pauses the node in the cluster, which prevents the node from being and becoming the PAM.
Sets the value of the DatabaseCopyAutoActivationPolicy parameter on the DAG member to Blocked.
Moves all active databases currently hosted on the DAG member to other DAG members.
If the DAG member currently owns the default cluster group, the script moves the default cluster group (and therefore the PAM role) to another DAG member.