There are two important glitches that I have come across in star fortress heroic mode.

1.) Sometimes the exarch (of whatever the final boss's name is) turns invulnerable during the robots+siphon stage (that there are three of). When players kill the photoelectric droids, pickup and use the siphon, and overload the console, sometimes the exarch does not drop down and move to next stage as he should. He will remain floating in his forcefield while no new NPC mobs will spawn. The only solution to this is to reset the entire flashpoint and start from scratch.

We are unsure what triggers it, but it might have something to do with using the siphon and overloading the console too quickly while on a laggy connection of some sort.

2.) Sometimes when using the grapple thing to move between the platforms, a player suffers some sort of rubberbanding off the edge of the destination platform and instadie. Yesterday I witnessed a player die in such a manner three times in succession, although it has not happened to me personally.

ps. ADDITIONALLY, although not related to star fortress, I really wish devs could fix the invisible stone slab stairs on eternity vault story mode (Soa's chamber). I think that is close to gamebreaking when it happens. I know this bug existed before 4.0 but its really jarring and needs to be fixed.