Luck of the Sea is not functioning as intended. Instead of increasing chance to fish up treasure it seems to decrease it.
After 130+ fishing catches with a Luck of the Sea III fishing rod zero treasure items were fished up. I would expect that if it were functioning normally I would have an average of 12-13 treasure items.
Thank you for your report!
We're tracking this issue in MC-183325, so this ticket is being resolved and linked as a duplicate.
That ticket has already been resolved as working as intended, which means this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.
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