Subtitle Editor: Subtitles for a newly uploaded VTT file are not displayed in Paella Player

[mwuttke]

Uploading a VTT via the editor does not work properly if a video does not yet have a subtitle.

If you upload a VTT file via the editor or create it there, it is correctly assigned to the event and also displayed in the admin ui under Actions -> Show video details -> Attachments -> Media. It can also be downloaded there. However, the subtitles created in this way are not displayed in the Paella Player.

However, uploading a new VTT in the editor works if an Amber/Whisper subtitle already exists. The old subtitle will be overwritten correctly in this case.

tested Opencast Version: 15.7