S60 QLabel major render problem on certain FP2 devices such as XpressMusic 5730 RM-465

On specific S60 FP2 devices there are rendering issues with widgets including QLabel, QMessageBox and QListWidget. This is with the latest S60 QT build environment as of time of writing of this bug.

The bug is never seen the first time an application is executed after rebooting the device. After that, it occurs around 75% of the time. Waiting before running the app again seems to help, but not always.

In QLabel, the bug manifests as multiple lines wrapping with the wrapped lines not appearing below the previous line but on the same line. The label then looks garbled.

In QMessageBox, the result is that the message text does not appear; instead there are but a few small dots. The same occurs for QListWidget, no items appear, only a few dots at the top of the list.

I suspect these widget issues are related.

A test project is attached that demonstrates the QLabel issue.

This bug manifests systematically on my XpressMusic 5730. Device troubleshooting, included upgrading the device to latest FW, hard reset, etc...

This does NOT happen on N79 RM-348.

Note that other computers with the same build environment produce builds that have the same issues.