Certain objects atop busted blocks are not affected by gravity

Some ground-based objects and object sets are capable of falling onto bustable blocks (regular and spin), but once said blocks are broken, they stay suspended in mid-air.

Known affected objects:

• Pop-up turrets (not regular ones)
• Robo-hoods
• Crushstaceans
• Green Snappers
• Star posts
• All monitors
• All springs (except horizontal)
• Fans
• Gas jets

As far as I know, all other ground-based objects (Crawlas, pushables, solid decorations, etc.) fall as they're supposed to.

Attached is a GIF of the bug in action with a Crushstacean.