This article provides detailed explanations of the Issue Reports available in PPO:
The report includes all the fields on the Issues entity for all issue records and projects. If the “Include Project Information” checkbox is selected, the report will also include all the fields on the project entity.
The Issue History Report shows when the issue was updated, by whom and what the recent issue action/response was. This provides a complete view of how the issue has changed over the lifespan of the project.
The Issue Report shows all the current issue information (no history records are shown on this report).