Why doesn't my jigsaw connection work, when it worked in the past?

I have done other jigsaw based structures before. Even managed to do a quite complex one, but now, it doesn't want to work. What could be the problem? The jigsaws point to each other, I double checked everything, I'm out of ideas. I try to make hexagons generate next to each other Structure set: { "placement": { "type": "minecraft:random_spread", "salt": 14357618, "separation": 5, "spacing": 9 }, "structures": [ { "structure": "b723:hex_pillars", "weight": 1 } ] } structure: { "type": "minecraft:jigsaw", "biomes": [ "b723:wastes-1" ], "step": "surface_structures", "spawn_overrides": {}, "terrain_adaptation": "beard_thin", "start_pool": "b723:hex_origin", "size": 7, "start_height": { "absolute": 0 }, "project_start_to_heightmap": "WORLD_SURFACE_WG", "max_distance_from_center": 80, "use_expansion_hack": true }