13.518 Error ClientMultiplayerManager.cpp:1094: mod-skins-factored was registered for the following nth_ticks when the map was saved but has not re-registered them as a result of loading: 1

How did you get this to happen, did you try to join a dedicated server or another player hosting a game? I tested this code in multiplayer and it worked for me, but I might've made a mistake.

its my server, after update mods i received this error

This should be fixed in version 1.3.3 of Skins Factored (the library this mod uses); use Factorio to update all your installed mods, and make sure the server also has the updated version.