Greetings fellow Inquisition members!
I too have had the same problem. I would imagine that ordinarily a person would simply complete Sera's Crestwood quest/mission retrieve the reward and that should cause the game to offer the 'World Map' option. I'd guess that something in code isn't setting the flag appropriately to display the World Map button upon completion of the mission.
I would considder loading my old save game but the problem is that Sera is my character's LI/RI (Love Interest) as such, I don't see a way around this problem until it gets patched or until a workaround can be found. Until then I guess I will be hanging out in Crestwood for a while until a patch is finally released Or a workaround is made available.