Custom dimension & biome - void_start_platform not spawning

Hey! So I made a datapack which adds a new, empty dimension, and gave it a custom biome which is basically a copy of minecraft:the_void. Everything works fine - I am able to teleport to the new dimension using commands, the biome is being spawned there, but it lacks the minecraft:void_start_platform (it is included in the new biome's .json) How could I fix that?