A clash in Navisworks can only be connected to one issue in the BCF Manager.
When you want to import new clashes from the Clash detective as issues, the import window will show information about which clashes are already linked to an issue in BIMcollab.
Due to the filter function of the BCF Manager, it is possible not all issues are loaded in the current issue list. To verify which clashes are already linked to issues, click the 'Lookup in BIMcollab' button at the bottom of the import window. This button will load all issues connected to the clashes in the current clash list, also the ones outside of the filter. After having clicked on the button, the issue information in the clash list will be up-to-date.
📝 Note: The 'Lookup in BIMcollab' button will not open the selected issues in the browser.