Reg 5.9.6 -> 5.11.1: QStyle::drawControl(QStyle::CE_ProgressBar) fails on Mac

What you will see in the attached demo application is a QStyledItemDelegate that overrides paint() and draws a progress bar with the following call:

option.widget->style()->drawControl(QStyle::CE_ProgressBar, &optProgress, painter);

This is what it looks like on Mac with Qt 5.9.6, and same on Windows with any Qt version:

And this - on Mac with Qt 5.11.1. The two progress bars should be identical, but they're not. And I don't think either of them should be drawn in the "disabled" state.

When I started fiddling with the demo code, neither of the progress bars was being displayed at all, the table looked blank. Unfortunately, I changed something in the progress bar options, and I can't find a way to make the bars invisible again. But I guess it's the same bug, and the behavior of the demo program is sufficiently broken already: