The bug
When in a world with LAN turned on, structure blocks are not functional and don't have a name displayed above them.
Linked issues
discovered while testing
Attachments
Comments


@unknown, the issue with command blocks has its own ticket: MC-88632. Also both tickets are assigned to Searge, which means they are not WAI.

I can confirm that this issues also appears in Windows 10 (Minecraft 1.12.2) when open to LAN with cheats off.
However, even if I (the player running the server) can confirm that I still have cheats, I can not bring up the menu on a structure block.
Importantly though, a second player joining the server (in creative mode) could assess the GUI on the structure block.
It is interesting to note that this second player could not place structure blocks, despite seemingly being the sole player capable of operating a structure block.

Partially blocked by MC-123784

Unable to reproduce in 20w07a. Loading structures works when opened to LAN.
This is not a bug, in the LAN settings, you can enable or disable cheats. When cheats are disabled you can not use structure blocks or command blocks.