I was able to place a block on top of the block I was standing on while shift clicking in the Nether. I was also able to walk around the block while shift clicking. Block also does not produce sound when placing down it down.
Was unable to replicate successfully in a new world but I was able to replicate the glitch successfully multiple times in the survival world where it had happened. I'm unsure of the cause but I had a tamed wolf which had teleported through the Nether portal in a sitting position and I suspect it may have something to do with the tamed wolf.
Confirmed. This seems to happen everytime you enter the nether and lasts for a short while. I suspect this has something to do with chunk generation / conversion happening at the same time.