Plains of Golghein Strongbox - AP Reset
Submit a support ticket (following the link from the top left).
The only time I’ve heard of AP resetting (that wasn’t associated with someone disconnecting or the Rollback of 2016) is the one associated with the Hall of Monuments — that’s a known glitch with a long history that won’t apply to other achievements.
It also might be easiest simply to reopen these two strongboxes rather than wait for Support to help you troubleshoot, pass along details to the QA team, and waiting for them to resolve the issue.
Good luck and please let us know what you find out.
John Smith: “you should kill monsters, because killing monsters is awesome.”
I’ll re-obtain the strongboxes in the weekend and will keep you posted.