Where the mountains are blocks in the air without being attached to the mountain

Do you have Experimental Gameplay - Caves And Cliffs toggled on?

Yes, this must be experimental gameplay if blocks generate at Y 183.

In 1.17.11 Hotfix this X, Z coordinate generates a coastal desert village, not a mountain.

From the screenshot it just looks like normal terrain generation. Floating islands are common in Minecraft. This is working as intended: see MCPE-17525.