QSGGeometry defaultAtttibutes_ColoredPoint2D causing overflow with too many vertices

When adding over 65536 vertices to a QSGGeometry initialized with defaultAttributes_ColoredPoint2D, the position of vertices after the 65536th are drawn not drawn at the position assigned to them, but at the position of earlier vertices starting from the initial vertex added.

Attached is a example project, change the numberof_horzontaldivision variable in Grid_M.hpp to 220 to show the overflow.