Again an Iron Horse issue (which I believe was also reported repeatedly in the old forums), this time while fighting Morozova:
Sometimes the adds carrying the so badly needed rockets do not spawn anymore at all or do spawn so slowly that even with killing them right away and directly shooting the rocket, you will not be able to destroy the Earthshaker's grenade. This usually happens in the second, third, or fourth phase of the Morozova fight. And for us it seems to happen randomly – although I think that it miiiiiiight occur more often on Tuesdays and Wednesdays.
Yesterday I measured approx. 55 seconds between two adds spawning (the first one was killed right after spawning on top of his watchtower and the rocket was fired immediately).
I also opened a ticket including a video from yesterday's raid.