I have the same exact problem and just posted on the forum about it. I have no idea what to do to prevent her from doing it. I've done all the same things you have! I have to buy a new dock every couple months! If you come across any solutions let me know!
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"We can judge the heart of a man by his treatment of animals"
--Immanual Kant

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1 Dog (Oliver)
1 RES (Siggy- 12 years old)
RIP Tyson (Dog)
RIP Lucky (Turtle)