Adding subtitles with FFMpegCore in C# is not working on Azure Function

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I have deployed a C# azure function with ffmpeg.exe (using FFMpegCore nuget). The function adds audio and srt/ass subtitles to a video.
When I test locally this code works (running on azurite). But, when I deploy the azure function, the audio is added to the video but the subtitles don’t show up.

At the begining I thought it was an issue with the Fonts because I was using ASS File for subtitles but then I switched to SRT and still is not working.

I’ve tried with both SRT and ASS but they both don’t work using this code:

await FFMpegArguments
 .FromFileInput(videoInputPath, true, options =>
 {
     options.WithCustomArgument("-stream_loop -1");
 })
 .AddFileInput(audioPath, true)
 .OutputToFile(videoOutputPath, true, (options) =>
 {
     options.WithDuration(thread.AudioData.TotalAudioDuration);

     options.WithVideoCodec(VideoCodec.LibX264);   // Re-encode video using x264 codec
     options.WithAudioCodec(AudioCodec.Aac);       // Re-encode audio to AAC
     options.WithSpeedPreset(Speed.VeryFast);
     options.UsingShortest(true);

     options.WithVideoFilters((videoOptions) =>
     {
         videoOptions.HardBurnSubtitle(SubtitleHardBurnOptions.Create(subtitlesFile));
     });
 }).ProcessAsynchronously();

Here’s the command it creates on Azure function:

ffmpeg -stream_loop -1 -i "C:\local\Temp\videoTempPath.mp4" -i "C:\local\Temp\audioTempPath.mp3" -t 00:00:22.8160000 -c:v libx264 -c:a aac -preset veryfast -shortest -vf "subtitles="C\:\\local\\Temp\\subtitles.srt"" "C:\local\Temp\output.mp4" -y

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