A scripted object (probably SingularityGroup.HotReload.HotReloadSettingsObject?) has a different serialization layout when loading. (Read 56 bytes but expected 76 bytes)
Did you #ifdef UNITY_EDITOR a section of your serialized properties in any of your scripts?

Server: Fresh install 

Server: No Plugin

Same problem here. It started from the weigh with a (ai-wolf-prefab) That would be missing. After the steamcmd update of 07-02-2025 my Custom map no longer works. I also updated Oxide on 07-02-2025. I just had a map generated but that was not really successful either. Generating a map is possible but train tracks half off the gondola. Roads and rails too high above each other, making passing impossible. Oxide launched today 08-02-2025 2nd update in 2 days. There is an Oxide Update every week. I can't remember an update in years without errors. With steamcmd the problems are less frequent, but apparently game over for custom servers. An acquaintance of mine who raises a server at a third party and has no problems. When I look at the list of mod servers at rest. Are there still servers with custom maps active. I have huge doubts about this. Do the owners Clouds that they sublet, in rust servers?. I don't want to offend anyone but the fun of hosting is gone. I have worked Rgames. Later Fivem server. Minecraft server. I have my own Cloud. What a Pointer I would say is. Every rust update. Rust takes too much unnecessary time. Errors variables that could have been prevented. That really a sin? When I studied bebage. I wonder why interns work on rust updates. Or are developers forced to rent servers?

Merged post

NullReferenceException: Object reference not set to an instance of an object
NullReferenceException: Object reference not set to an instance of an object
NullReferenceException: Object reference not set to an instance of an object
NullReferenceException: Object reference not set to an instance of an object
at ServerMgr.Update () [0x00769] in <cd08dd64d3744d71b10432a69e89404e>:0
UnityEngine.DebugLogHandler:Internal_LogException(Exception, Object) 38fps 171gc 34m25s
UnityEngine.DebugLogHandler:LogException(Exception, Object) 580b/s in, 256b/s out
UnityEngine.Logger:LogException(Exception, Object)
UnityEngine.Debug:LogException(Exception, Object)
ServerMgr:Update()

got same message here