Imported data from other programs may contain details that are inconsistent or incomplete. Some of these can be corrected by checking the project database statistics and exceptions.
Often unwanted empty Facts can be imported such as Death Events that can disrupt some displays.
Use the All Empty Facts Query, sort into Fact order, and delete any unwanted empty Facts, by selecting those Facts and pressing the Delete key.
Statistics and Exceptions
Install and run the Show Project Statistics plugin and check the details on all tabs. Any shown in red may need investigation and correction.
On closing the Plugin it presents a Result Set Exceptions Report for all statistics marked in red with direct links to each item.
Check its Help & Advice pages for full details.