If you pick up water, while quickly moving your mouse, it fills the bucket, but does not create a new infinite water source. Items also glitch in this empty space, couldn't show it due to the size of the video. did not try it in creative or normal survival, only hardcore. If it's seed-specific, here is the seed of my world:   (coordinates are visible in the video). This glitch/bug only seems to work, when the water source is one block deep, haven't been able to recreate it with any deeper water. Placing water with the bucket on the affected space seems to fix it.

Edit: I was now able to recreate it on waterblocks deeper than 1 block. Same world. those spaces cant be fixed though, because you can't place a waterbucket in midair.