One reason why a newly created event name may not arrive in mParticle is because you have breached your workspace's event limit. By default, this is set at 1000.
When the limit is breached, the new unique event names over the limit are dropped from incoming data. This will be characterized by the new event missing from the batch and the batch showing up as an eventless batch or the new event missing from the batch's events.
This limit is configurable, but proliferating unique event names usually indicate problems with your data and can impact performance of both the mParticle dashboard and your apps, therefore it will not be raised except where absolutely necessary.
In general, this behavior is seen with dynamic event names, e.g., "page_view_tools", "page_view_tools_rake", "page_view_tools_rake_spring", "page_view_tools_rake_steel". In this scenario, custom attributes should be used to capture the categories after the word "page_view".
An easy way to test this scenario is to send in a previously seen event and verify that it shows up in Livestream and then send the new event in and verify it is dropped from the batch.
When you encounter this scenario, please submit a support ticket via to have Technical Services confirm the limit was breached. In addition to raising your unique event limit, you may want to look into a data point cleanup to hide unwanted data points from the mParticle dashboard.