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What part of the tree are the brackets attached to? The main trunk? Big branches? Branches certainly move. I think they can become more or less vertically oriented relative to the stem over time, so that could be a difference. They also get thicker, so that could be a difference.
GO
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Another possibility is that the unloading of the stump by removal of the tree above caused it to gradually release towards a more neutral position. This could have caused all of the other trees bound together by the platform to shift laterally with rotation and vertical movement. I can imagine this if the removed tree had an unbalanced weight distribution, perhaps with a large branch off to one side.
Ken