I see this when people leave VC: Unhandled voice opcode received: 13 {"op":13,"d":{"user_id":"…"}}

Apparently op: 13 means ‘Client Disconnect’. (And 7 and 9 are ‘Resume’ and ‘Resumed’ respectively.)

https://discord.com/developers/docs/topics/opcodes-and-status-codes#voice

Perhaps unrelated, but sometimes I see people in VC in the Ripcord sidebar, even though they're not (and don't show as such in the official client.)

https://dev.cancel.fm/tktview?name=178626dd8b