Far away claimed resource plot = confusing red X?

Scenario: I claimed a far away resource plot (e.g. iron). I then decided to build a facility (e.g. iron mining) on that plot. I clicked the building icon in the build list then hovered over the plot with the mouse. The mouse cursor was a red (X) with no red requirement/warning text. I clicked and built the building with no discernible issues. I had plenty of money and resources.

I would have attached a screenshot but it doesn't capture the mouse cursor.