If I download 3rd party freeware scenery for this airstrip, CYBA, then I get the extra scenery graphics ALONG WITH THE WHITE & OPAQUE CHEQURED RUNWAY. Very weird! If I remove these 3 NAVIGRAPH FOLDERS THEN THE 3RD PARTY FREEWARE SCENERY WORKS FINE! 
If I download 3rd party freeware scenery for this airstrip, CYBA, then I get the extra scenery graphics ALONG WITH THE WHITE & OPAQUE CHEQURED RUNWAY. Very weird! If I remove these 3 NAVIGRAPH FOLDERS THEN THE 3RD PARTY FREEWARE SCENERY WORKS FINE!