I just applied this buff then started an adventure and it isn't showing on the adventure which generally means you don't get credit for it. It comes up in system information as being applied first and it showed up on my game screen applied first and nothing.

No did not get the extra xp from this adventure. The second one I did is showing the buff though so it appears to be some sort of timing thing - but if the system recognizes the buff is applied first both on the island screen and in the system chat, it should be applying the buff to the adventure.

I had made a ticket and included screenshots if you want to verify the timing of everything. Don't want to post them here because I would have to block out a bunch of guild chat as well.