Aggressive mobs cannot pathfind around dripleaves, I waited 60 seconds, while moving around and the zombie couldn't move, as shown in the video, there are two ways to do this shown in the video.
EDIT: video exceeded the limit so made a google drive link,
https://drive.google.com/file/d/1paZs1Kfbd4xpaGqI710Tw_qaP78C7R0R/view?usp=sharing
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We're tracking this issue in MC-181565, so this ticket is being resolved and linked as a duplicate.
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