The bug
In 20w06a the names for {{smooth_quartz}} and {{bamboo_sapling}} were changed to "Smooth Quartz Block" and "Bamboo Shoot". Despite this, their IDs weren't updated. This also affect other files such as textures, models, recipes, advancements and loot tables.
Expected result
The aforementioned IDs would be smooth_quartz_block
and bamboo_shoot
.
Can confirm for bamboo.