First, you can visit your Proposal Dashboard, which is a group of charts, tasks, and overall progress of your team.
The system helps, by notifying and reminding writers and approvers. But you can also run some reports that might be helpful.
If you go to the Tasks page, you can filter on tasks to identify people who completed their tasks after the due date (they were late).
Configure the filter to show Completed writer tasks. I often look at a specific Proposal, but you can leave this unchecked and the system will look across all Proposals.
You can even filter on Writer Completed and pick a specific date. This is great to identify anyone who missed a specific Proposal due date (like that every happens).