Use ++$h{$_} instead of $h{$_}++ so the incrementing is done first, before the compare. $h{$_}++ returns the value, which is numerically 0 the first time through, then increments the value. This causes things seen only once to be ignored.

@toBeMoved = sort {$a <=> $b} grep {++$h{$_} == 1} @toBeMoved;
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