You are converting that lovely string you build into an integer to store it in that variable on the game instance…
Change type of that var (and presumably the equivalent in your actual save bp), most sensible thing to do I think is to actually use a Date Time type:
and connect up Now() directly, but use string if that is what you really want of course.
Any time you see that ‘dot’ node something is being type converted, if you are not expecting that, something is amiss!