When a player pours water on max build height, they get two things.
#1: Jump boost
#2: (with elytra equipped) Flight into the air without rockets. The player can keep flying until the elytra breaks. My friend made a youtube video about it - It's short but it shows how the glitch works: https://www.youtube.com/watch?v=kuSle0FCt_8
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Thank you for your report!
However, we are already tracking this issue, and this report is a Duplicate of MC-90026, which is a report that has not been resolved yet.
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