Closely relates to MC-136405.
The bug
Unlike most blocks, when right clicking on a replaceable block such as a vine, if the player is holding a lily pad or frogspawn, that block will not be placed even if it would have been placed in a valid position.
How to reproduce
Create a setup with vines against a wall above water
Right click on the vines, intending to replace them with a held lily pad
Attempt to place the lily pad atop the water directly instead
Expected results
When targeting the vines, the lily pad would be placed.
Actual results
It is not. The lily pad is placed just fine, replacing the vine, if the water is targeted instead.
Related issues
relates to
Attachments
Comments

I can confirm this behavior.