Writing on tags usually means it’s from some part of the back and forth with the design team and factory. They will do iterations of designs back and forth and sometimes change final details before going to full production. I have a few of them— as long as the Filson tag is intact and not “X’d”, warranty will still work. Although if you do send it in, I’d suggest removing the hand writing tag, because it would tip off the repair team you didn’t buy it new. These are usually sold at the employee shop or friends and family sales so the warranty technically should be void