I have noticed that there are sometimes more numbers in the email than shown in the UI.
This may be because some flow runs have been cleaned up. The best thing to monitor with would be FlowStudioApp and keep an eye on your flow.
A resubmission is a "new flow" run and will incorporate any changes you have made to fix any problematic actions.
Therefore the original will remain in the failed state.
You can capture errors and set the run to successful but this will make your flow more complex, as it could error at any action etc.
The resubmission runs with the latest version of the flow, whereas the failed one could of run of a previous version.
For instance if there was a action that was causing the flow to fail then a resubmission would avoid this action if the action has been deleted.
Hope that helps clear this up 🙂 But yes if its successfully running = no email.