Feel free to rename the ticket, wasn't sure what to call it.

When a prefab, such as GameMode_Base.et is open while loading a mission that relies on it, such as CTI_Arland_Campaign.ent. You will be unable to join a squad when the mission starts. If the mission is stopped & started again you will be met with multiple VMEs.

Video posted below with first bug reproduced & without the reproduction to show that it would work otherwise.
https://cdn.discordapp.com/attachments/750841570500018229/1266433040394092635/2024-Jul-26_12-29-02handbrake.mp4?ex=66a5212e&is=66a3cfae&hm=fd1d6ececf46a7327f49f9c45b3dc9f5349b066a9e7cbee1bdc1581ceab83ba0&