This isn't a bug at all. Novetus Snapshot starts a Client and Server for solo as it was the original way Roblox did it (Roblox would start a server in the backend for one player, and then it opens a client to join it). This makes testing places and features for multiplayer much easier, as places in solo would function differently to how they'd work online. This means chat, leaderboards, and everything would work the same as it would on a normal Novetus/Roblox server.