Hey there @Apex14291! Welcome back to the community! My recommendation is to have a single object, likely the game state to hold your random function and decide who is infected. Making the variable a RepNotify and using an RPC to send it’s decision to all players should sync that correctly.
Disclaimer: One or more of these links are unaffiliated with Epic Games. Epic Games is not liable for anything that may occur outside of this Unreal Engine domain. Please exercise your best judgment when following links outside of the forums.