As the title says.. Lily pads can be placed when the player is in adventure mode, it can also be placed outside the world border

Lily pads unlike other blocks, can be placed when a player is in adventure mode(which should'nt be possible)
The same with outside world border.. other blocks can't be placed outside the world border even when the player is in creative mode, but lil pads are not affected by this, they can be placed outside the world border

Steps to reproduce
1. /worldborder set 5 in game
2. Try and place a Lily pad outside the world border
3. /gamemode adventure and try to place a lily pad on a water source block