You need to make changes in your data model, make a key between more than one field...
It happened because two tables must have just one link.
Example: JOIN, CONCATENATE or QUALIFY the tables.
take a look in this material
You have two tables that both have the fields Office City and Country. Qlik Sense uses the common fields to associate the tables. When there are two or more common fields then a synthetic key is created. Apparently in one or both of your two tables the Country or Office City field is sometimes empty. That means that there are combinations of Country and Office City that only exist in one of the two tables. With the result you see.
How to fix it? That depends on what you think is correct data. Should there be records where Country of Office City is empty? How should those records then be linked to the other table? You could simply rename one of the fields in one of the tables so only the one remaining common field is used to associate the tables. But you'll have to decide if that solves your problem or only hides a data quality issue.