The recent update of Photoshop, 24.7.0, seems to have broken PCX exporting. Yes, the PCX's still load and open, but the color tables are getting their indices reversed. So the color that was Index 0 is becoming Index 255, Index 1 is becoming 254, ect.
The following images show a before and after. The first shows the color table in our source PSD after flattening all layers and applying our .ACT file. The second image shows the color table of the PCX file saved out by photoshop.
This issue is not occuring in the preceeding ersion, 24.6.