pac admin assign-user is failing with "WAM Error Need User interaction"

[Thomas-Chabot]

The code I'm running is:
pac admin assign-user --environment "https://environment-name.crm3.dynamics.com" --user $userId --role "System Administrator" --application-user

This works if I run it locally, but if I try to run it from within an Azure DevOps pipeline, it's failing with the error message:

Microsoft PowerPlatform CLI
Version: 1.24.3+g95fc6ea

Error: WAM Error  
Error Code: 3399548929 
Error Message: Need user interaction to continue. 
Internal Error Code: 527291998

I haven't been able to find any results when searching for the error. Because it's in DevOps I'm not able to give it the user interaction, but we do have the pac authentication already set up (we're running some other commands through pac, such as importing a solution, and those are fine).