Right after switching realms between Zoom, OpenID (Ping), or LDAP, Zoom apps still show the login prompt for the previous realm. The correct login prompt is shown only after the user attempts to log in using the old login prompt and the login fails. All subsequent login prompts on that user workstation are then shown correctly.
However, this first login after the realm switch can be fixed on a user workstation by making a call to the server. Right after updating to the new realm, the user should run a zm command, like zm getservers or zm creds. This will refresh the .zm with the latest realm information and all logins after that will show the correct prompt.