Did you get contacting d2 servers or a black screen any time during it?
This is a 7 hour run, so if you too a break at any point an stayed in the dungeon but got contacting servers that will invalidate you run.
Dungeon report has it as a fresh solo run also, an it sounds like it was a smooth run, no contacting servers, error codes, or anything like that.
This must be bugged at the moment then, id take a look at there known issues to see if this is on there.
Unfortunately bungie never makes triumphs like this retroactive.
Take a look see if this is on there known issues if it is, you'll have to run it again once they fix it, if not hopefully a mod can reply an maybe they can give more insight.