correct_ans_latex_string that the results table uses.
You are right, the correct_ans_latex_string is to correct. The sum should not actually have correct_ans_latex_string set, but it is inheriting the one from the (0,2] accidentally.
One solution work-around for now would be to use
$range = ($range1 + $range2)->inherit;
(I know that sounds wrong, but it is the right thing.)
I wil make a fix and submit a pull request.l