Farm Tiles can be built on top of other tiles, then all tiles are inaccessible

Created a row of farm tiles from ladder to ladder, the first two were created then the rest were ignored and the Dupes traveled around the area. I set the priority to 9 for the remaining center Farm Tiles how ever the Dupes ever went near them. I tired to cancel the build process and remove the two currently built Farm tiles at the ends by the ladders. I tried to recreate the room, how ever it was placing jobs on top of jobs. 

DxDiag.txt

Launch Pad McDuck.sav

output_log.txt