This orange/boomerang indicator is available for chats for the messaging apps only. It appears if the chat is boomeranged (came back to being active). This happens 12 hours after the initial/previous conversation took place. Once the agents log in again, they will receive all the chats from 12 hours ago that had the Boomerang option enabled. The chat is automatically closed after 3 boomerangs or 24 hours of inactivity.
The agent will also see the message “Chat boomeranged” in the conversation field. This doesn’t mean, however, the visitor initiated the chat. In that case, the agents can start the chat on their side. Each time the same customer starts a chat, the boomerang option will be automatically enabled, even if disabled the previous time. In that case, the agent needs to make sure to disable this function in case it is not required.