Messenger Inactive Visitor Updates
Salesforce cannot push notifications to distributed Send2CRM clients, they must receive message data in the response to visitor updates initiated from the client. If a website visitor remains completely inactive then new messages from Salesforce or changes to business hours may not be received.
Messenger resolves this by implementing an inactive update with a longer timeout setting, 10 minutes by default. If a visitor is identified and no update has been sent for this length of time, one will be forced to ensure that any new information from Salesforce is retrieved.
This overrides the standard behavior of Send2CRM, whereby visitor updates are not made unless there is new behavior to send. In normal circumstances this reduces unnecessary API calls, so we generally advise that the inactive update frequency should be longer than the standard Send2CRM sync frequency.