When you activate an Energy Converter, the beam will fire and its sound will be heard.
However, if you get killed by some enemy at that moment, the sound will still play, even when it should be immediately stopped, when your ship was destroyed.
2 same related bugs:
Same issue applies for Pyro Emitter (same sound bug) - destroyer module
ECM: Metastable Field bubble (same sound bug) - ECM special module
Logs: (check logs near the end - Custom battle - 17:47+ or 5:47+PM)
[2017.04.29 16.58.05.zip](< base_url >/applications/core/interface/file/attachment.php?id=14143)