Bubble chart series not pulling calculated column values

What is the challenge?

I've created a calculated column that I would like to reference as the series for a bubble chart however, the calculated column values are not recognized as options in the series on my bubble chart.

What is the impact?

The bubble chart series only shows (blank) so I cannot use my calculated value as the series.

Describe your idea

I'm specifically looking at initiative due date to generate a Now/Next/Later value based on days until due. I would like to create a bubble chart that colors the bubbles using the Now/Next/Later value.