Debugger: iOS: Cannot stop debugging on device (without closing QC)

Steps to reproduce:

• create Quick Application from template (I've used Qt5.4.1 official release)
• place a bp into the main.cpp ( QQmlApplicationEngine engine; ) and another inside main.qml ( Qt.quit(); )
• start debugging
  • 1st bp is hit -> Continue
• touch 'Hello World' on the device
  • 2nd bp is hit -> Stop

Expected result:

• debugger shuts down and QC is in state to start debugging again

Current result:

• debugger engine becomes ill
• all buttons of the debugger toolbar and respective menu items inside the Debug menu are disabled
• cmdline shows some QTC_ASSERTs
• using 'Debug' -> 'Abort Debugging' does not help
• trying to hit the Stop button of Application Output or trying to close the repective tab of the Application Output does not help either

Note: it seems as if the inferior and the debugger has stopped already but this information has not been given back to QC. The only way to get a usable QC back is to close QC in a normal way and kill the application afterwards (or use Ctrl+C) as it also fails to close at all.