I've had this happen twice in the last week on the same toon; After the skirmish immediately after opening the initial blast door, I am stuck in combat mode for the entire duration of the alert -- even after finishing Grodd. The combat indicator remains stuck in the "ON" position and my health and power do not regenerate. In the absence of a Healer or Controller (friends and I usually run this in DPS) I have to continually chug Soders. Since we like to walk-in as all-DPS duos or trios on this alert, I do not feel we should be forced to run the party "in role".
This has been happening for quite some time in that alert. From what i gather, the rooms that open periodically when your in that first big room still release a couple of enemies after you hit the required 30 to open the door and they tend to insta-aggro you from several rooms away but will never actually catch up to you. If you have ever seen them coming from behind you when you go to hit the 2 switches for the next door you know what i mean. Occasionally sitting still for a couple of seconds will de-aggro you. I dont know why they hold aggro so long but that is what i have noticed.
This^... Yh its the prisoners in the last cell you dont have to clear that causes this, just stay a few seconds longer and kill them thats what I do.