Hi folks, we've been seeing some reports about this specific issue and Sr. Server Programmer Jennifer Harkness wanted to elaborate a bit on what's been going on:
However, we have run into one unexpected effect. Normally when you zone to a new area, we try to put you in the same instance as your guild mates and friends. Unfortunately, it's doing the same thing when you zone into raid instances, which means that with the lowered population numbers, you can be the last one who fits in the instance, and there won't be room for the rest of your Operations group. This is why a few people have been getting the dreaded "Server Admin" error and end up unable to zone into Denova.
Can you please pass on to Jennifer the following important information? The dreaded "Server Admin" error most often happens for my group (and others I am familiar with) not when Denova instances are FULL but rather when they are EMPTY. That is, when all other operations have left that Denova instance and only our group is remaining, with 1-2 people in the instance being the only ones, and the remainder stuck outside.
I'd like to add that the other issue seems like a simple fix: disable the friend-matching instancing for operations, flashpoints, warzones, etc...