Qt OPC-UA Water Pump example crashes in normal mode, runs OK in debug mode

The Qt OPC-UA example water pump demo crashes when run in normal mode, but runs OK when run in debug mode. (which makes it hard to try to figure out where it is crashing)

*we might be dealing with a difficult timing bug here. Debug mode runs much slower.

expected: It doesn't crash when run in normal mode.

As the instructions say, the simulation server needs to be built and started up in order to run the water pump demo. It's located in the same folder with the water pump demo.