Bucket doesn't collect water/lava just after it spreads

Update from [~GoldenHelmet]

This issue affects both water and lava, and seems to be due to how the server thread handles liquid flow state updates. On MCPE-100598 it was noted that

If the player attempts to pick up the water/lava within this duration (a short number of ticks after the liquid starts to spread), the hotbar will register the lava being picked up for a split second but then will flash back to the empty bucket. The server does not detect the client picking up the liquid either.

.... For whatever reason, [it appears that] the bedrock server engine converts the solid liquid into flowing liquid for a few ticks to allow the solid liquid to start flowing, and then quickly converts the source block back to a liquid "block", which then can be picked up with a bucket. Of course, flowing water or lava cannot be picked up with a bucket, so I think this is the culprit.

This theory also explains another observation reported on MCPE-80911:

When picking up lava with a bucket and quickly placing it on a neighbouring lava source, it completely disappears.

Found an issue since 1.10 that when emptying and trying to collect the water immediately its not collecting the water. Makes it difficult when you can't collect it and pushes you backwards. Found this issue on Xbox One, not a beta version.