Backlog [Bug] Emrakul, The Promised End does not grant more extra turns if cast multiple times on the same turn

[Mikail]

Casting two copies of [Emrakul, the Promised End] does not give the opponent two extra turns.

According to this thread it occurs for a while: https://github.com/PennyDreadfulMTG/modo-bugs/issues/385

Recent example: