That is a common issue when placing junctions in a curve, as the linked messages mention. Always straighten the trailing leg leading into a junction, the lower leg of the Y. Make sure the two upper legs, the through and diverging tracks, are not straightened. If two facing or two trailing junctions are in a row, always place a spline joint between them so that two straightened sections of track are not directly connected. Two non-straightened sections or a straightened and a non-straightened can be connected without any issues.