Assert failure when stopping an animator

ASSERT: "!job->isRunning()" in file util/qquickanimatorjob.cpp, line 223

import QtQuick 2.7
import QtQuick.Window 2.2

Window {
    id: window
    visible: true

    OpacityAnimator {
        id: animator
        running: true
        loops: Animation.Infinite
        target: window.contentItem
    }

    MouseArea {
        anchors.fill: parent
        onClicked: animator.stop()
    }
}

#0  0x00007ffff52236f5 in raise () at /lib64/libc.so.6
#1  0x00007ffff52252fa in abort () at /lib64/libc.so.6
#2  0x00007ffff639524f in qt_message_fatal(QtMsgType, QMessageLogContext const&, QString const&) (context=..., message=...) at global/qlogging.cpp:1683
#3  0x00007ffff639168e in QMessageLogger::fatal(char const*, ...) const (this=0x7fffffff9f10, msg=0x7ffff66cfc50 "ASSERT: \"%s\" in file %s, line %d") at global/qlogging.cpp:795
#4  0x00007ffff6389bf4 in qt_assert(char const*, char const*, int) (assertion=0x7ffff7c25767 "!job->isRunning()", file=0x7ffff7c256c6 "util/qquickanimatorjob.cpp", line=223) at global/qglobal.cpp:3004
#5  0x00007ffff7966953 in qquick_syncback_helper(QAbstractAnimationJob*) (job=0x824dc0) at util/qquickanimatorjob.cpp:223
#6  0x00007ffff7966a05 in QQuickAnimatorProxyJob::syncBackCurrentValues() (this=0x824e80) at util/qquickanimatorjob.cpp:237
#7  0x00007ffff796649f in QQuickAnimatorProxyJob::updateState(QAbstractAnimationJob::State, QAbstractAnimationJob::State) (this=0x824e80, newState=QAbstractAnimationJob::Stopped)
    at util/qquickanimatorjob.cpp:169
#8  0x00007ffff6f2ca54 in QAbstractAnimationJob::setState(QAbstractAnimationJob::State) (this=0x824e90, newState=QAbstractAnimationJob::Stopped) at animations/qabstractanimationjob.cpp:366
#9  0x00007ffff6f2d21c in QAbstractAnimationJob::stop() (this=0x824e90) at animations/qabstractanimationjob.cpp:536
#10 0x00007ffff7907f4e in QQuickAbstractAnimation::setRunning(bool) (this=0xa2bfc0, r=false) at util/qquickanimation.cpp:290
#11 0x00007ffff7908629 in QQuickAbstractAnimation::stop() (this=0xa2bfc0) at util/qquickanimation.cpp:544