While crouching (holding shift) at the edge of the farmland block, at the very edge it doesn't allow the player to walk forwards or backward from the edge of the block. Instead, you have to either stop crouching and run off or jump off.
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Thank you for your report!
However, we are already tracking this issue, and this report is a Duplicate of MC-188987, which is a report that has not been resolved yet.
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