The secondary's can only be read only. That would likely not be able to to be changed. I know changing the owner does not propagate. I have had to do that. You need to fail over and then change it.
Try making the change on one of the DB's on the secondary. If it works, then changing the primary should propagate to the secondary's. If it will not let you make that change, then you will need to fail it over.
A trick I used was to create a SQL job that executes a script to change the owner on each database. Add an alert for 1480 (ag failover) that calls this job and changes it. You will have to test if the server is the primary before executing the script, the alert should get fired on all of the nodes. You can do the same thing, but the script would change the page verify option.