Verify concommand is registered before attempting to execute it.

lua/ulib/shared/commands.lua

@@ -1370,7 +1370,11 @@ if SERVER then
 
 	local function hookRoute( ply, command, argv )
 		if #argv > 0 then
-			concommand.Run( ply, table.remove( argv, 1 ), argv )
+			local arg1 = table.remove( argv, 1 )
+			local commandTable, _ = concommand.GetTable()
+			if commandTable[arg1] ~= nil then
+				concommand.Run( ply, arg1, argv )
+			end
 		end
 	end
 	concommand.Add( "_u", hookRoute )

ulib.build

@@ -1 +1 @@
-1507560100
+1517743950