While in creative mode on my server, placing a command block while flying and holding both Spacebar and Left Shift so I could place a command block on top of another without opening its menu, the block was placed correctly but was unable to be accessed. When right clicking on the new block, it appeared that my character was attempting to place another block on the command block instead of opening its menu. The block would appear and then immediately disappear, with the sound of placing a block heard. In order to get around this, I had to break the command block and place another. The new command block was accessible with no problems.
I saw a similar issue of command blocks being inaccessible after death, but I had not died during the time this happened, and had in fact placed other command blocks just fine only moments before.
What I expected to happen was...:
I expected the new command block to be accessible.
What actually happened was...:
It was not accessible.
Steps to Reproduce:
I have been unable to reproduce the bug, as after I left and reconnected, I could place the command blocks without issue. I have a video of me demonstrating the issue, but the video file is too large to upload (900 MB).
This is not a LAN server, correct? You probably experienced some desync.