Mob breaks blocks badly ( Not solved )

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In short, I'm creating a mob that should break blocks with this AI block,

BUT at the same time, after the mob has broken the block, the block should be replaced by another one, And this AI block is broken, it works very strangely, the mob can only break the block if it stands over the block, and if it can't get to it, then it doesn't pay attention at all.

?What should I do?

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