the command "/execute positioned over (heightmap)" doesnt work in snapshot 8

Minecraft has the command “/execute positioned over (heightmap)” which used to work however in 26.8 it now throws an error even tho Minecraft itself suggest the options. The error being:
Could not parse command: Cannot invoke "com.mojang.serialization.Codec.parse(com.mojang.serialization.DynamicOps, Object)" because "this.codec" is null

Steps to reproduce: open chat and type: “/execute positioned over ocean_floor“
Expected result: it works
Actual Result: the word “ocean_floor“ is red and throws an error when you run it even tho its suggested by the game as a valid option