Installed 1.5.1 and the bug is still present but changed. In 1.4.6, the step placed when I stepped off toward the right. In 1.5.1 the bug now goes off the left. I can record a new video demonstrating the bug off the left if needed.
Our server runs on 1.4.6/1.4.7, which is why I have 1.4.7 installed and reported it as a problem with 1.4.7. I won't be updating to 1.5 until our server updates, if we do. While I realize 1.5 is the latest, it only went live a few days ago and none of the servers I play on have updated yet. I will update once our server and the other servers I frequent update and report at that time whether the bug continues.
I have confirmed the bug in two different worlds, two different servers, and asked a friend to replicate the bug on his machine.
As originally indicated above in the "affected versions", the affected version is 1.4.7. I do not have 1.5 installed. Do you mean that I should update some other affected version category?
A decrease on the Z axis seems to trigger it, but I'm also seeing that I can place a step on another step even though my head is occupying that space. This is true without any movement on any axis. That was not true in 1.4.6, that I know of.