@Splice, sorry to hear this. Disabling the handgun skins is a bandaid solution for now while we are trying to resolve the underlying issue. Unfortunately, these skins were not disabled for Offline mode - which was an oversight on our part, apologies for that.
We will be able to disable the handgun skins for Offline mode too and apply the bandaid fix, but it will require a backend update, which should then fix this error on startup for you. I don’t have an ETA just yet, but I’ll continue to check in with our backend developers about this.
Unfortunately, as you’re an Offline mode player, there isn’t anything more immediate we can do as we can’t access your local save data directly; and deleting your local save data would delete all Offline mode progress.
Please bear with us, and hopefully we can get an Offline mode backend fix out soon!