Today I was doing the new temple instance with a group and after we killed azzy, i ran my enforcer into the temple to loot OD, but the first portal had de-spawned. After looking at the other portals we noticed no timer was in the description, and no portal expire time was listed in any guide. The group was thinking it was a bug. I have the incident streamed, and recorded.
The portal on the first floor always despawns after a certain time.