What’s wrong with mixing 2 metaphors in the same sentence ?

Mixed metaphors are frowned on because they create a confusion instead of a fusion of effects, like the 'Irish bull' about the man who, whenever he opened his mouth, put his foot in it

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particulars about treasure island, from the beginning to the end, keeping nothing back but the bearings of the island, and that only because there is still treasure not yet lifted, i take up my pen in the year of grace and go back to the time when my father kept th

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