Snowmen don't place snow layers below y=67

How to reproduce

• Summon a snowman at y=67 with a block below him at y=66
  → The snowman places a snow layer at his feet
• Summon a snowman at y=66 with a block below him at y=65
  → The snowman doesn't place a snow layer at his feet

Note: This only occurs in a plains biome