You are right. You can't see it by applying Title to the same track as
the purple background, but by putting Title in an empty upper track
the problem is still there.
Thing is, patch only alters dissolve plugin, and not titler (our titler and one in cinHV differentiate quite far)
But then I tried to reconstruct test case with red and white2 png (rgb from cinHV tests folder) on same track with dissolve transition
between them and even unpatched cingg was ok in all modes (yuva-8, rgb-8 ...) ?