No posterFrame in wowza player on Apple devices since iOS 14.1 uppdate

Wowza Player
1

Hi there,
in my wowza player, there is no longer a poster frame shown on iOS devices.
Last month it worked well, but now there is only a black screen with a play button.
On other devices it is working.
My code is

<script type="text/javascript">
var wowza_player = WowzaPlayer.create("wowza_player",
    {
    "license":"PLAY2-blablabla",
    "sources":[{
    "sourceURL":"https://cdn3.wowza.com/1blablabla/hls/live/playlist.m3u8"
    },
    {
    "sourceURL":""
    }],
    "title":"",
    "description":"",
    "autoPlay":false,
    "mute":false,
    "volume":75,
    "posterFrameURL":"https://example/images/teaser.jpg"
    }
);
</script>

Can anyone confirm this behaviour?

Thanks in advance.