Bug:

When saving a structure with a structure block using a button, a lever or a pressure plate, it will not save the structure to the disk and will be gone as soon as you quit your world. When you're saving a structure normally by clicking "SAVE", it will save to the disk.

How to Reproduce:

• Give yourslef a structure block (/give @s structure_block 1)
• Place the structure block and right next to it a button/lever/pressure plate
• Save a structure in the structure block by clicking the button next to it
• Save and quit the world and then rejoin and try to load the structure again