Across various boots of the same qemu image, I find that a random app may fail to launch. The symptom is a blank application surface after clicking on the icon. The log shows the following in this case:

Mar 31 15:12:36 qemux86-64 daemon.err afm-user-daemon[368]: ERROR: start error user unit afm-appli-hvac@0.1.service: inactive [/usr/src/debug/af-main/1.0-r0/git/src/afm-urun.
Mar 31 15:12:36 qemux86-64 HomeScreen[426]: launch "hvac@0.1"
Mar 31 15:12:36 qemux86-64 HomeScreen[426]: pid: -1
Mar 31 15:12:36 qemux86-64 HomeScreen[426]: qml: app cannot be launched!

Once this happens, it's natural to click on the icon again after switching back to the HomeScreen. This will result in a launch:

Mar 31 15:13:04 qemux86-64 HomeScreen[426]: launch "hvac@0.1"
Mar 31 15:13:04 qemux86-64 HomeScreenAppFrameworkBinderAGL[353]: launchApp name: hvac@0.1
Mar 31 15:13:04 qemux86-64 HomeScreenAppFrameworkBinderAGL[353]: jsonLaunch

{"id":"hvac@0.1", "mode":"local"}

Mar 31 15:13:04 qemux86-64 HomeScreenAppFrameworkBinderAGL[353]: stateString

{ "runid": 880, "pids": [ 880 ], "state": "running", "id": "hvac@0.1" }

Mar 31 15:13:04 qemux86-64 HomeScreenAppFrameworkBinderAGL[353]: pid 880
Mar 31 15:13:04 qemux86-64 HomeScreenAppFrameworkBinderAGL[353]: launchApp pid: 880
Mar 31 15:13:04 qemux86-64 HomeScreen[426]: pid: 880
Mar 31 15:13:04 qemux86-64 HomeScreen[426]: makeMeVisible 880
Mar 31 15:13:04 qemux86-64 WindowManager[395]: =[showAppLayer]=
Mar 31 15:13:04 qemux86-64 WindowManager[395]: pid 880
Mar 31 15:13:04 qemux86-64 WindowManager[395]: No layer to show for app(pid=880)
Mar 31 15:13:04 qemux86-64 WindowManager[395]: Screen render order 0, 1 layers

Other applications seem to launch fine the first time and then the WM has no problem finding their layer to show. It seems that if an app fails to launch the first time like that then when it does launch the second time it doesn't seem to have a layer associated with it for the WM to handle.

The other thing is that there is indeed a hvac process running, so other than no visible app layer, the app is running on the system.

Note that hvac is just an example here. By reboot and clicking different apps I've made this happen to settings and phone as well. Sometimes it's the first app I attempt to launch and sometimes it's the 3rd or 5th...I can't isolate a pattern to reproduces it except attempting to launch several apps.