Cant Place Blocks In Certain Spaces

I have found an area where blocks cannot be placed. Looks like its 4 blocks that will not place down. I have tried different blocks and this still doesnt work. 

Block just appears then dissapears. No errors shown on server console etc. 

If you download and unzip the attachments (seperated in parts) you will see a video of this occurring. I had to do it this way as you cannot screenshot the problem.