Silence is ignoring set notification sound.
I'm on LineageOS 16 with MicroG.
Silence is ignoring notification sound set inside the app and keeps using system default notification sounds.
For example, like now I have selected "Aldebaran" under Settings-Notifications-Sound, but when I receive SMS, I get notification with default system sound which is "Adara". :)
Others apps (Telegram, WhatsApp, etc) are using proper notification sounds set inside their settings, so this is specific to Silence.