DialogueWave playback calls OnQueueSubtitles multiple times

DialogueWave playback calls OnQueueSubtitles multiple times, whereas playing normal SoundCues only call it once at the start of playback.

1. Put a breakpoint at the start of FSubtitleManager::QueueSubtitles(const FQueueSubtitleParams& QueueSubtitleParams) in SubtitleManager.cpp
2. Start the attached project from Visual Studio in Development Editor configuration but with "-game" parameter passed as a command line argument (can use UnrealVS for this)
3. See that the breakpoint gets hit continually.

Desired result: breakpoint is hit once, when the subtitles are played