A team member with the role of viewer can only view issues within the project, but can't edit anything.
You can also give team members the role of reviewer.
In this case, they will be able to leave comments and approve issues when they are added to the approval list. They will not be able to edit the issue itself.
The role of the Editor for Documents will also limit a team member from editing the issues.
📝 Note: If you would like to read more about roles in a project, you can use this article: Roles within the BIMcollab environment.