subtitleStreamID always "-1" while polling the timeline

[jeffaries]

I am polling the time line from a home made controller. I notice that the subtitleStreamID attribute of the timeline response always equals -1 (whatever the subtitle selected from the UI)
I have tested with an official PMP from Plex. There the subtitleStreamID is correctly updated

Here is an exemple of the response:
<?xml version="1.0" encoding="UTF-8"?> <MediaContainer machineIdentifier="76858271e30d89e3-com-plexapp-android" size="3" commandID="26"> <Timeline itemType="music" controllable="playPause,stop,volume,shuffle,repeat,seekTo,skipPrevious,skipNext,stepBack,stepForward" state="stopped" type="music" /> <Timeline itemType="photo" controllable="skipPrevious,skipNext,stop" state="stopped" type="photo" /> <Timeline audioStreamID="3616" itemType="video" playQueueVersion="1" address="192-168-3-9.4a15a9b8d7c34ee9a05afc728f140840.plex.direct" playbackTime="576527" machineIdentifier="d6bc11bdc007f4812195351074d72eb005c66498" ratingKey="10" type="video" url="null" token="wQG8HoAtM45wgsrcgptm" volume="0" duration="5839715" protocol="https" playQueueID="138" subtitleStreamID="-1" port="32400" playQueueItemID="235" controllable="playPause,stop,volume,audioStream,subtitleStream,seekTo,skipPrevious,skipNext,stepBack,stepForward" containerKey="/playQueues/138" guid="com.plexapp.agents.imdb://tt5220122?lang=en" state="playing" time="568447" key="/library/metadata/10" /> </MediaContainer>

OpenPHT: [1.8.0.149, Plex Black edition, Windows 64]
PMS: 1.14.0.5470

[Update] The theme is not involved... I have the issue with every themes