ArcGIS Pro 2.2.4
Repo steps below.
Hi Dan,
I believe this is a known bug captured in BUG-000116327 In Legend Properties, the 'Only show features visible in the map extent' option fails to function when a feature class is symbolized using unique values in more than one field.
This bug also affects other renderers, such as graduated color, that use expressions (see BUG-000118169 When symbolizing the layer with an ‘ARCADE EXPRESSION’ in graduated colors, the legend in the layout does not show correct number of features present in each category in ArcGIS Pro.)
Hopefully, we can address this issue in the near future.
Thanks for the feedback.
Tom