Issues can be used to identify errors or aspects of concern within models & drawings. Issues can be created on certain file types. In CUBE, Issues can be created in any 2D drawing or 3D model to highlight a certain point that needs rectification from a particular stakeholder.
Standalone Issues, not pertaining to any single file, can also be created.
These articles will help you understand the Issue management features in CUBE and how you can create an Issue and track it till the time it is resolved.

The Issues Tab from the left panel in CUBE will show a complete list of Issues that have been created for your project and quickly assess its progress. Together with the image and the markups, the statuses are visible. The properties panel on the Issue management page allows users to track comments made by stakeholders allocated to the problem.
Sounds interesting? Refer to these articles related to Issue management for a deeper dive.
File-related Issues - These Issues are the ones that are particularly associated with a singular file whenever any user faces Issues directly linked to specific files, such as drawings, models, or documents. These Issues are often identified during the review or coordination process when team members interact with project files.
Standalone Issue - These can be created without any reference; that is, these are general problems or tasks that need to be addressed, independent of documents or models.