The bug

Unlike structure blocks, jigsaw blocks do not send any message saying a structure/piece was successfully loaded.

Steps to reproduce

1. Summon a jigsaw block with all of the necessary data already inputted in it and a grass block beside it by using the commands provided below.

   /setblock ~1 ~ ~1 minecraft:jigsaw[orientation=north_up]{final_state:"minecraft:structure_void",joint:"rollable",name:"minecraft:building_entrance",pool:"minecraft:village/plains/houses",target:"minecraft:building_entrance"}

   /setblock ~1 ~ ~ minecraft:grass_block

2. Open the jigsaw block and set the "Levels" value to "1" and then click the "Generate" button.
3. Notice how there is not success message upon the structure being generated.