I haven't seen any posts on this topic for a while, but I wanted to let everyone know that this is still a thing. However, after playing around in there this week, my group noticed that the freeze-frame lag in there seems to be caused when players enter/leave the instance. So coming up from the base, or going down to the base. We tried it out while going down to turn in telvar, and the frames froze each and every time a player went down (we let the squishies go first).
With the layoffs, I don't know if there is any staff working on this particular issue, but if so, hopefully this will give them a lead as to what could be causing the problem.