Qt chart does not always show the best fit line correctly

Following cases have been tested in both Qt6.2.7 and Qt6.5.5 (test file(test-1.py) has also been attached)

#Case 1:  points = [[2, -26.957], [3, -23.022]]

#Case 2: points = [[ -26.957, 2], [-23.022, 3]]

#Case 3: points = [[0.5, 1], [0.5, 2], [0.5,3]]

Qt6.2.7 generates best fit line in case 1, but does not generate the best fit line in case 2 and 3.

Qt6.5.5 generates best fit line in case 1, and 2 but does not generate the best fit line in case 3.