Semitransparent models are not correctly blended

In the attached example 2 semitransparent models are rotating around one another.
Instead of blending the models one of them is rendered in front of the other. Rendering order changes on the fly causing flickering. In some moments both models are painted behind the ground, in the others one of them is painted in front of the ground. Self-blending also doesn't look good.

There was similar problem in 6.0.0 beta5: https://bugreports.qt.io/browse/QTBUG-88925
Can the fix be ported to 6.2.0 ?