Place water on a vine and then try to collect it from the block below.
It should be picked up normally but it becomes invisible and aside. ...
If I place water on a vine and then collect it with a bucket from the block below it, it gives the illusion that it disappears, but it remains there invisible. However, if I collect it with a bucket from the vine itself, then it does disappear.
This issue is being tracked at MCPE-218044.