Table regularity fails but same number of columns in each row/rows in each column

[Emily242146696qj7]

Hello, 

I am getting a regularity issue for the table below, even though there are the same number of columns in each row/rows in each column. A note that I had to build this table within the PDF. Not sure if that makes a difference. Can anyone tell me why I would be getting this error when all looks ok?