Desert temples generate way to high in superflat worlds. This happens in every supeflat desert world to any desert temple.
superflat worlds have some problems with the new depth limit (since21w06a)
Desert pyramids generate underground when using amplified or custom terrain
Superflat worlds start generating at negative coordinates, causing a dark horizon
Snow layers in "Snowy Kingdom" superflat preset generate 64 blocks above the ground
Ocean Monuments in Water World presets don't spawn correctly