Lily pads generate on blocks within structures

I saw a lilypad generating on a block, which i think doesn't work as intended.

Reproduce

Seed: -2673931441407680092
Coordinates: /execute in minecraft:overworld run tp @s -116236.51 61.88 3907.52 -565.53 22.00 

Expected Result

The lily pad wouldn't generate on blocks that aren't ice or water