An LJ formatting puzzle

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A LJ puzzle.
I my journal,nested comments seem to display properly, up to at least seven levels deep?
In Debbie's  virtual birthday party only the top two levels show, and you have to click to see comments deeper than that.
Why are they different?

Comments

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comment level 1

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comment level 2

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comment level 3

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comment level 4

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comment level 5

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comment level 6

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comment level 7

[blueeyedtigress]

Volume on the page, pure and simple.