The table violates first normal form's rule that all cell values must be unique. See below.
You cannot have two values in one cell. This would introduce numerous problems. You would not be able to do joins on this column. Nor would grouping on the column work correctly. Sorting would not work and so on.
To resolve this issue you need to update the table to correct this entry. below is the corrected table.
This table now has no issues that violate first normal form but it WILL violate second. We will discuss that in our next post.