After the patch on November 10th I intended to redo the last Undine PvE quests and noticed that the fights were suddenly a lot more 'tougher'.
During these fights, when the health bar of the enemy NPC ship got to 90%, 70% and sometimes 40% (based on about 6 observations / space NPC fights) the health of the Undine ship suddenly restored to 100%. I even had one occurrance where a dreadnought went from 3% to 100% in a fraction of a second.
They're not using Hazard Emitters or Engineering Team, since their ship does not show any buff at all.
This occurred on the second-to-last and last Undine quest-chain, space-combat. I logged back out and in before I started the last quest, but to no avail.
I'm unsure if this was a once-in-a-lifetime occurrance, but I did log out and back in before starting the last Undine mission and the issue above was still happening.
My fleetmates told me they had no problems fighting other ships (none of them were busy with the Undine PvE quests, so this might be an Undine-only issue).