Using Custom Campaign Text As Analysis Filters

Hi All: I'm starting to use custom campaign text in an Analysis report I am building out and keep running into this error message (see screenshot below):

I'm not sure why the expected value is numeric, as this is a text field. When I double checked the field settings (Setup -> Fields & Views -> Campaign Fields), I confirmed that it was in fact set to being a "text" field (see screenshot below).

Essentially, what I am trying to do is filter my table based off a number of different custom campaign values - vertical, profile and practice area (essentially a "product", but not quite - hence the custom field).

Any help would be greatly appreciated!

Thanks,

Kyle