When doing so in a normal (non-crew) match, it seems to simply drop you off at the "local" menu (i was testing in local) after selecting the stage, while trying to do so in crew battle with my workshop characters on the same team, the game crashes entirely
This seems to be a loading problem, as when i do them one at a time, the issue that sends me back to the local menu seems to stop. The crew battle error persists regardless, though
Also if it is relevant: this was tested using Armando and Blender Default Cube by Nino Nezumi