Start debugging with Attach to QML Port: Gives popup "Internal error: Unsupported start mode 7."

Starting debugger "QmlCppEngine" for ABI "x86-windows-msvc2015-pe-32bit"...
 Start parameters: '' mode: 7
 ABI: x86-windows-msvc2015-pe-32bit
 Languages: qml
 Debugger: C:\Program Files (x86)\Windows Kits\10\Debuggers\x86\cdb.exe
 Remote: :0
 QML server: localhost:62090
 Sysroot:
 Debug Source Location:
 Debugger settings:
 AdditionalArguments: (default: )
 AdjustBreakpointLocations: true (default: true)
 AllPluginBreakpoints: true (default: true)
 AlwaysAdjustColumnWidths: true (default: true)
 AutoDerefPointers: true (default: true)
 AutoEnrichParameters: true (default: true)
 AutoQuit: false (default: false)
 BreakEvent: (default: )
 BreakOnAbort: false (default: false)
 BreakOnCatch: false (default: false)
 BreakOnCrtDbgReport: false (default: false)
 BreakOnFatal: false (default: false)
 BreakOnThrow: false (default: false)
 BreakOnWarning: false (default: false)
 BreakpointCorrection: true (default: true)
 BreakpointsFullPath: false (default: false)
 CDB_Console: false (default: false)
 CloseBuffersOnExit: false (default: false)
 CloseMemoryBuffersOnExit: true (default: true)
 DisplayStringLimit: 100 (default: 100)
 EnableReverseDebugging: false (default: false)
 ExtraDumperFile: (default: )
 FontSizeFollowsEditor: false (default: false)
 GdbCustomDumperCommands: (default: )
 GdbPostAttachCommands: (default: )
 GdbStartupCommands: (default: )
 IdentifyDebugInfoPackages: false (default: false)
 IgnoreFirstChanceAccessViolation: false (default: false)
 IntelFlavor: false (default: false)
 LoadGdbDumpers2: false (default: false)
 LoadGdbInit: true (default: true)
 LogTimeStamps: false (default: false)
 MaximalStackDepth: 20 (default: 20)
 MaximalStringLength: 10000 (default: 10000)
 MultiInferior: false (default: false)
 NoPluginBreakpoints: false (default: false)
 QmlInspector.ShowAppOnTop: true (default: false) ***
 RaiseOnInterrupt: true (default: true)
 RegisterForPostMortem: false (default: false)
 SelectedPluginBreakpoints: false (default: false)
 SelectedPluginBreakpointsPattern: .* (default: .*)
 ShowQObjectNames2: true (default: true)
 ShowQmlObjectTree: true (default: true)
 ShowQtNamespace: true (default: true)
 ShowStandardNamespace: true (default: true)
 ShowThreadNames: false (default: false)
 SkipKnownFrames: false (default: false)
 SortStructMembers: true (default: true)
 SourcePaths: (default: )
 StationaryEditorWhileStepping: false (default: false)
 SwitchModeOnExit: false (default: false)
 SymbolPaths: (default: )
 TargetAsync: false (default: false)
 UseAddressInBreakpointsView: false (default: false)
 UseAddressInStackView: false (default: false)
 UseAlternatingRowColours: false (default: false)
 UseCodeModel: true (default: true)
 UseDebuggingHelper: true (default: true)
 UseDynamicType: true (default: true)
 UseMessageBoxForSignals: true (default: true)
 UsePythonDumper: true (default: true)
 UseToolTips: true (default: true)
 UseToolTipsInBreakpointsView: true (default: false) ***
 UseToolTipsInBreakpointsView: true (default: true)
 UseToolTipsInLocalsView: true (default: false) ***
 WarnOnReleaseBuilds: true (default: true)
 WatchdogTimeout: 20 (default: 20)
 State changed from DebuggerNotReady(0) to EngineSetupRequested(1) [master]
 CALL: SETUP ENGINE
 State changed from DebuggerNotReady(0) to EngineSetupRequested(1)
 CALL: SETUP SLAVE ENGINE
 NOTE: ENGINE SETUP OK
 State changed from EngineSetupRequested(1) to EngineSetupOk(3)
 CALL: SETUP INFERIOR
 State changed from DebuggerNotReady(0) to EngineSetupRequested(1)
 CALL: SETUP SLAVE ENGINE
 ERROR: Internal error: Unsupported start mode 7.
 NOTE: ENGINE SETUP FAILED
 State changed from EngineSetupRequested(1) to EngineSetupFailed(2)
 NOTE: ENGINE SETUP FAILED
 State changed from EngineSetupRequested(1) to EngineSetupFailed(2) [master]
 <Debugging has failed
 State changed from EngineSetupFailed(2) to DebuggerFinished(22) [master]
 State changed from EngineSetupFailed(2) to DebuggerFinished(22)
 QUIT DEBUGGER REQUESTED IN STATE 22