Carpet collision does not block spawns

Steps to reproduce

1. Load Carpet spawns.mcworld (this world has been opened in 1.21.0.20 Preview).
2. Fly up to Y 130 and watch the platform.
3. If 8 non-spider mobs spawn, run /kill @e and watch for a while longer.

Expected result

Spiders would not spawn.

Observered

Spiders spawn on the stone where they collide with carpet.