Hey, Dragon Eagle.
This artifacting is known, but it's not necessarily an issue.
If you navigate to your FPS Creator folder, and open up the setup file with NotePad, you'll find a setting called "lightmapquality."
The default setting is 5, so just add a 0 right in the text document to change it to "50."
Next, just close FPS Creator, then restart it. Ensure that in your Preferences, you selected Full Lightmapping and Full Shader Effects, along with High Texture Quality, and the artifacting should disappear.
Good luck, and tell me if it works! I hope it does for you!

My Computer Specifications: Intel i7 980x OC @ 4.2 GHz |3x GTX 580's in SLI | 12 GB, 2000 MHz RAM (Corsair) |2x 1 TB HDD | 1.2 KW PSU |ASUS Rampage III Extreme Motherboard