Not Sure Is This Bugs Or WAI? Because I Typing Jigsaw Blocks

"Target Pool:" minecraft:woodland_mansion

" Name:" minecraft:building_entrance

"Target Name:" minecraft:building_entrance

"Turns into:" minecraft:structure_void

And I Click Generate (button) It Does Not Work And I Tryed Multiplie Times But It Not Work, But Villages Works

Sorry But I Don't Have Screenshot But You Can Reproduce Here As You Why Not Work.