Right in the middle of the Mirror Universe Event the Mirror Universe missions have been removed from the game last night.
Reason: With yesterdays patch the rewards for PVE queues have been adjusted. For "Mirror Incursion Adv." (MIA -> that pefectly describes the condition of the mission) the dilithium rewards suddenly raised to 7400 per run, instead of 740 dil. So... a small typo with big effect.
While this time I dont bother about such immediate actions I have to ask myself why it was required to remove all mirror universe missions (in the middle of a running event) instead of just fixing that reward number.