This is what I got out of the .crash file:

#0  0x00000000 in ?? ()
No symbol table info available.
#1  0xa90b3d2c in android_camera_enumerate_supported_thumbnail_sizes (n1=0x429ed8, 
    n2=0xa9a236d9 <AalImageEncoderControl::getThumbnailSizeCb(void*, int, int)>, n3=<optimized out>) at camera.c:110
        f = 0x0
#2  0xa9a20b12 in AalCameraService::initControls (this=this@entry=0x4356d0, camControl=camControl@entry=0x429ed8, listener=0x4429e8)
    at aalcameraservice.cpp:269
No locals.
#3  0xa9a20bcc in AalCameraService::connectCamera (this=0x4356d0) at aalcameraservice.cpp:173
        device = <optimized out>
#4  0xa9a1f9bc in AalCameraControl::setState (this=0x435d88, state=QCamera::ActiveState) at aalcameracontrol.cpp:48
        ok = <optimized out>
#5  0xb0a41be2 in QCameraPrivate::setState (this=0x44a4e0, newState=QCamera::ActiveState) at camera/qcamera.cpp:115
No locals.
#6  0xb69d7e80 in QQmlObjectCreator::finalize (this=0x4038e8, interrupt=...) at qml/qqmlobjectcreator.cpp:1226
        profiler = {profiler = 0x0}
        watcher = {sharedState = {d = 0x403970}, watcher = {_t = 0x403970, _r = false}}
        ocRestorer = {ep = 0xc2040, oldCreator = 0x0}
#7  0xb69898e0 in QQmlComponentPrivate::complete (enginePriv=0xc2040, state=0x1b2778) at qml/qqmlcomponent.cpp:936
        interrupt = {mode = QQmlInstantiationInterrupt::None, {timer = {t1 = 3065572233, t2 = 17774258302430336}, nsecs = 0}, 
          runWhile = 0x0}
        state = 0x1b2778
        enginePriv = 0xc2040
#8  0xb698995c in QQmlComponentPrivate::completeCreate (this=0x1b2718) at qml/qqmlcomponent.cpp:972
No locals.
#9  0xb698b328 in QQmlComponent::createObject (this=<optimized out>, args=0xbe991bd8) at qml/qqmlcomponent.cpp:1249
        parent = <optimized out>
        rv = 0x432c80
        scope = {engine = 0xc2a98, mark = 0xb1100370}
        valuemap = {ptr = 0xb1100370}
        ctxt = <optimized out>
        object = {ptr = 0xb1100380}
#10 0xb6a2321c in QQmlComponent::qt_static_metacall (_o=_o@entry=0x1b5090, _c=_c@entry=QMetaObject::InvokeMetaMethod, _id=_id@entry=6, 
    _a=_a@entry=0xbe991bf8) at .moc/moc_qqmlcomponent.cpp:145
        _t = 0x1b5090
#11 0xb6a23322 in QQmlComponent::qt_metacall (this=0x1b5090, _c=QMetaObject::InvokeMetaMethod, _id=6, _a=0xbe991bf8)
    at .moc/moc_qqmlcomponent.cpp:208
No locals.
#12 0xb69604e8 in QV4::QObjectMethod::callInternal (this=<optimized out>, callData=0xb1100310) at jsruntime/qv4qobjectwrapper.cpp:1868
        rv = {ptr = 0xb1100360}
        qmlGlobal = <optimized out>
        func = {callData = 0xb1100310, retVal = {ptr = 0xb1100360}, ctx = 0x3f0a38, e = 0xc2510}
        funcptr = 0xbe991bd8
        args = {0x0, 0xbe991bbc}
        v8Engine = 0xc2510
        scope = {engine = 0xc2a98, mark = 0xb1100360}
        method = {<QQmlPropertyRawData> = {{propType = 43, propTypeName = 0x2b <error: Cannot access memory at address 0x2b>}, 
            coreIndex = 11, {notifyIndex = 0, arguments = 0x0}, {{revision = 0, metaObjectOffset = 1, {{valueTypeFlags = 65534, 
                    valueTypePropType = 65535, valueTypeCoreIndex = 0}, {overrideIndexIsProperty = 0, overrideIndex = -1}}}, {
                accessors = 0x10000, accessorData = -2}}, flags = 4718912}, <No data fields>}
#13 0xb6967ab8 in call (d=0xb1100310, this=<optimized out>) at jsruntime/qv4object_p.h:270
No locals.
#14 QV4::Runtime::callProperty (context=0xbe991d5c, name=..., callData=...) at jsruntime/qv4runtime.cpp:938
        scope = {engine = 0xc2a98, mark = 0xb1100350}
        baseObject = {ptr = 0xb1100350}
        o = <optimized out>
#15 0xad57164e in ?? ()
No symbol table info available.
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Unfortunately it crashes on android side, so it doesn't give us too much data to go on, not without getting symbols for that... And it being non-reproducible around here, that might prove difficult :/