"is in" dropdown filter including blanks/empty rows

Hi all -

I am using a filter of the form text_variable “is in” dropdown_menu_selection - per the screenshots below.

That correctly filters out values of text_variablethat are not in the dropdown_menu_selection, but for some reason EMPTY text_variable values are still being returned - see below

I have tried removing any ‘blank entry’ from the list (see screenshot below; empty_cells is a text custom state that is empty), but (a) that has no impact, and (b) when I ‘count’ the list, no blank entries are showing up, so I don’t think any are there

Any idea what I’m missing here? Thanks for any advice!

Note that “intersect with”, as shown below, works - but I’m not sure why that works and ‘is in’ doesn’t