If a boat/boat with chest is entered while on a slime block, it will bounce.
To reproduce this:
•Place/ride a boat onto a slime block
•Get in the boat (get out and go back in if you are in the boat)
•Watch as the boat bounces
Note that being in the air while entering the boat significantly increases the height that the boat bounces.
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We're tracking this issue in MCPE-34577, so this ticket is being resolved and linked as a duplicate.
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