Bad QGraphicsPixmapItem scaling

We have an application with a QGraphicsView. The view shows a map made up by squared tiles. Each tile is a QGraphicsPixmapItem.

With some fractional scaling applied to the items, they are not properly scaled showing gaps between them

The problem disappears if the view is rendered using OpenGL or if a smoothing transformation is applied to the items.

We found this issue porting our application from Qt 5.15.9 to Qt 6. The items positioning and scaling was properly working in Qt 5.

Attached is an example showing the issue. In that example there are gaps between items in the 3rd and 4th column and row