Steps to reproduce

1. Pillar up 50 blocks.
2. Hold a water bucket.
3. Face straight down.
4. Step off the pillar and then start holding the "place" button (right mouse).

Expected result

When you get close to the ground you place the water and land in it safely, as in Java Edition.
Java holding place button.mp4

Observed result

When you get close to the ground you place the water, but most times you immediately pick it up again before you land and die of fall damage.
Bedrock holding place button.mp4

Placing and unplacing water + lava in the bedrock edition of the game is extremely buggy and unreliable, and this instability could lead to possible exploits within the game. 

There are 2 separate (but potentially intertwined) issues I have noticed on a regular basis, but for the sake of practicality, I will combine both issues into 1 report. 

The first issue being placement of water and lava when falling from a high velocity, often referred to as "MLG" or "bucket clutch", when a player places water (or even lava) below him or herself to prevent fall damage from a high place. After placing the water or lava (the initial placement is always reliable), more often than not, the liquid will pick up by itself without right clicking a second time. Whether or not the player takes fall damage seems to be completely random. Please note that I have tested this issue on multiple mice and I know it is not an issue with my input/double clicking accidentally. 

https://youtu.be/Lq2nKesQNac

The video above showcases the issue. This bug is incredibly frustrating because this feature of the game is well known in the technical survival java community, and bedrock edition players are unable to experience it. It is unfortunate that this happens because due to this bug, my maps which involve MLGing have been broken and PVP is a lot less reliable due to the bug.

Something else I noticed with trying to "MLG" or place water below you to prevent fall damage is that holding down right click the entire time from falling to landing is always reliable in preventing fall damage, as opposed to clicking right click to place the water when you are within reach distance of the surface you fall on. The caveat to this is that doing this method wutg a bucket in hand if you are falling from very high distances such as 100 blocks in the air does not work using this method. (lower distances such as 50 blocks work fine).

[Second issue removed as duplicate of MCPE-43960]