Steps to reproduce:
1. Download and open attached project.
2. Open scene named "MainMenu".
3. Enter the Play mode.
4. In the "Game" window press "START" button.
5. Notice that the "Console" window outputs this error message:

"InvalidProgramException: Invalid IL code in LobbyPlayer:CallRpcMakeInvalidCode (ExampleEnum[]): IL_0050: call 0x0a000017"

6. Open script named "Lobby" and temporary delete this line of code: "player.RpcMakeInvalidCode(listthree.ToArray());"
7. Notice that the issue disappeared.

Expected result:
The error message should not appear when passing array of enums to the method.

Reproduced with:
5.1.0f3, 5.2.4f1, 5.3.4f1, 5.3.5p1, 5.3.5f1, 5.4.0b18.

With 5.1.0f3 I get another error message and it does not allow me to reproduce the issue:
"Assets/Lobby.cs(24,26): error CS0115: `Lobby.OnLobbyServerPlayersReady()' is marked as an override but no suitable method found to override".