When creating an automation or a trigger and selecting a channel condition, you will see "Twitter DM" and "Twitter Direct Message".
The channel "Twitter DM" is the condition that you select if you do NOT have Agent Workspace enabled, and Twitter integration is added in Admin Center > Channel apps > Social Messaging channels.
While the "Twitter Direct Message" is the channel that you should choose if you have Agent Workspace enabled. For Twitter direct message channels in the Zendesk Agent Workspace, do not use the Twitter DM condition in your business rules and views. Use the Twitter Direct Message condition for these channels instead.