I have all 37 of 38 done except the 4th one of the 4 Ruin of Orr ones. I’ve done those four each twice to make sure I didn’t miss one. Is this a known bug or could I be doing something wrong? I sure wanted that mastery point!
Each of the dives is quirky. It’s impossible to be sure that you’re getting credit unless you are watching the counter increment a success or until someone figures out which dive # corresponds to which location.
Quirks include:
- Some dives have a very narrow spot that you have to hit, even if the destination seems to have plenty of room.
- Some dives require that you pass through something on the way down.
- Some require that you dive from the correct starting location.
- Some seem to require that you get returned to your armor; some don’t seem to care.
Since you know it’s one of the spots in Orr, I’d recommend trying the following:
- Visit with someone who hasn’t done one or more of these and let them go first. Make sure they get credit and then do what they do, step where they step, etc.
- Go with a mesmer (or be a mesmer) and use mimic+portal (set portal → dive → mimic → finish portal) so that you can repeat it a couple of times.
- Or just do each one 3-4 times.
In the days before these were numbered, a lot of us had to repeat the entire set (sometimes multiple times) to finally find the one that hadn’t triggered. In all the times I’ve responded to the posts, I’ve yet to find someone that wasn’t able to get credit eventually after repeated attempts.
tl;dr I’m pretty sure none are bugged; I’m pretty sure that most are so quirky it’s hard to tell the difference — so keep trying til it triggers for you.
John Smith: “you should kill monsters, because killing monsters is awesome.”
Thank you for your thorough answer. I’ll keep trying! 
Good luck! I hope it doesn’t take long. (And please let us know how it turns out.)
John Smith: “you should kill monsters, because killing monsters is awesome.”
I wanted to let you know I got the achievement, but I’m embarrassed to say how. There are 5 Ruins of Orr Diving Master Achievements, not four. I simply overlooked one – twice. I wanted to thank you anyhow. It encouraged me to keep trying!
Awesome; glad to hear it! (PS: you’re not alone. I mentioned that it was common, especially before HoT for people to have to re-try the full list of dives. What I didn’t mention is how many that mentioned that, in the end, it turned out to be ‘user error’ on their part.)
Thanks for letting us know you finished. And congratulations!
John Smith: “you should kill monsters, because killing monsters is awesome.”