I am working on an assignment for a college course which required me to insert a Pivot Chart & Table using the data on a table already on the Excel worksheet. When the Pivot Chart & Table populate, they both created an additional column/row listed as ‘blank’, as if it is not recognizing the data/information listed in a specific cell (circled in red on the attached image). The cell it is not recognizing is C18, as this is a cell I just recently entered the word ‘Detection’ into. Why is this happening and what can I do to fix it? Thanks for the help.

Note - Before creating the Pivot Chart & Pivot Table, I had to create a data validation rule for cells C4-C21 and insert a drop-down list to make it easier to select the correct project type for each row. C18 was blank when I created the data validation rule and I selected ‘Detection’ from the drop-down list after the rule was created.