Access Denied - Change Permissions required with User from Metadata

That message appears when there are permissions being handled using metadata card properties. It is to notify the users that the permissions are changing and it is a possibility that they may lose access. I did find it to be a bit annoying as well, and users found it confusing. Luckily there is a setting to disable that additional dialog from the admin client, if you want to . Here is a screen shot of where you can find that setting under the vault configurations:

That message appears when there are permissions being handled using metadata card properties. It is to notify the users that the permissions are changing and it is a possibility that they may lose access. I did find it to be a bit annoying as well, and users found it confusing. Luckily there is a setting to disable that additional dialog from the admin client, if you want to . Here is a screen shot of where you can find that setting under the vault configurations:

Thanks for your reply, however you might have misunderstood the "Error Message".
I was not talking about the Warning message but more about an "Access Denied Error Message"

The problem we're having is if you don't give the "Change Permissions" to a user or a group, they don't have the permission to change specfic property. 

Here goes an explicit example :

We have a Project property in a report object.
The report's accessible with r/w permissions by the mentioned project's technician only.
Alice is trying to change the Project Prop in the metadata card of the report.
If Alice doesn't have "Change Permissions", she can't change the project and save the modifications.

Hope it's clearer now.

This makes sense as your project property is driving permission on specific report object (using pseudo users or metadata-based security). In that case, your user effectively change permission on report when he/she assign new project. For that project's technician must have change permission rights.

We have similar case with drafters who need to add/remove certain approvers who are used to be assigned to have permissions on documents, so if drafter change approvers he/she effectively provides access to different users. For this change permissions rights are needed.