Well, I do recall Rip saying in Legends of Tomorrow that it takes time for changes in the past to set and affect the future. It was when he showed the team a vision of the future after Savage got a piece of Ray 's tech and explained that there was still time to prevent the future from changing. This could have a similar explanation. Or it could be that this is part of the new timeline after Barry undos the new timeline to reset things, but the "new" timeline is just the return of the old timeline with no changes or just a few minor changes (like how Barry travelling back in time to get the tachyon info from Eobard didn't change anything except make Hartley a good guy). Either way, it would be a wasted opportunity if nothing major ends up changing because of Flashpoint. This would have been the perfect opportunity to fix a lot of what went wrong with Arrow.