Swatches should show text colour when character style is applied
When a GREP Style applies a character style that includes a colour change the Swatches panel and the Fill in the Control Panel do not show the applied swatch. The swatch shown is for the base style without the GREP Style applied.
In the attaches screen shot the green text is affected by a GREP Style. As you can see the Swatches panel shows the text is black, not the applies swatch.
Scott Falkner commented
Further testing shows this bug does not appear if the entire range of affected text is selected.