ServerTravel not working properly

We have a matchmaking session, created by a server (a listen server) and joined by one or more clients.
Once joined, all the clients (and server) are correctly spawned on the map (the one chosen by the server).
At some point, the server wants everyone travels with them on a new map, so it calls the command "servertravel" by indicating the name of the new map.

If we perform it with the Null subsystem it works properly, and every player is spawned on the new map. The same is not true for the Oculus subsystem.
What we have is the following log:

[2017.10.19-10.10.16:027][880]LogNet: Browse: 1483781508382744.oculus//Game/Maps/Museo?game=/Game/Proteus_Multi/MultiGM.MultiGM_C
[2017.10.19-10.10.16:027][880]LogNet: World NetDriver shutdown OculusNetDriver_1 [GameNetDriver]
[2017.10.19-10.10.16:027][880]LogNet: DestroyNamedNetDriver OculusNetDriver_1 [GameNetDriver]
[2017.10.19-10.10.16:027][880]LogNet: UNetConnection::Close: [UNetConnection] RemoteAddr: 1483781508382744.oculus, Name: OculusNetConnection_1, Driver: GameNetDriver OculusNetDriver_1, IsServer: NO, PC: MultiPC_C_0, Owner: MultiPC_C_0, Channels: 39, Time: 2017.10.19-10.10.16
[2017.10.19-10.10.16:027][880]LogNet: UChannel::Close: Sending CloseBunch. ChIndex == 0. Name: [UChannel] ChIndex: 0, Closing: 0 [UNetConnection] RemoteAddr: 1483781508382744.oculus, Name: OculusNetConnection_1, Driver: GameNetDriver OculusNetDriver_1, IsServer: NO, PC: MultiPC_C_0, Owner: MultiPC_C_0
[2017.10.19-10.10.16:027][880]LogTemp:Display: ParseSettings for GameNetDriver
[2017.10.19-10.10.16:027][880]LogTemp:Display: ParseSettings for OculusNetDriver_2
[2017.10.19-10.10.16:027][880]LogTemp:Display: ParseSettings for PendingNetDriver
[2017.10.19-10.10.16:027][880]PacketHandlerLog: Loaded PacketHandler component: Engine.EngineHandlerComponentFactory (StatelessConnectHandlerComponent)
[2017.10.19-10.10.16:027][880]LogNet: UPendingNetGame::InitNetDriver: Sending hello. [UNetConnection] RemoteAddr: 1483781508382744.oculus, Name: OculusNetConnection_2, Driver: PendingNetDriver OculusNetDriver_2, IsServer: NO, PC: NULL, Owner: NULL
[2017.10.19-10.10.16:030][880]LogWorld:Warning: SetActiveLevelCollection attempted to use an out of date NetDriver: GameNetDriver
[A_LOT_OF_THIS_LAST_WARNING_REPEATED_ENDLESSLY]

We compared it with the behavior of the Null subsystem, and the logs are the same. Also on the Null subsystem it continuously prints this last warning log, but after some dozens of them, all players are correctly spawned on the destination map.

It works if we use a Seamless travel, but we really need to use a non-seamless travel (other components have problems with the seamless travel).

May you suggest something?