What you found makes sense as to why the problems is happening; it makes no sense why LCI makes it that way.
Are you thinking of adding a wide piece of metal on the inside linking (bolting) the "floating" channel to the actual door?
If the door is still nearly weightless, maybe removing a spring or two would put less strain on it as well? I only have 3 springs, as mentioned previously.
Attached drawing showing unattached bottom channel and new plate in green. I borrowed the drawing some else had made.
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