There are lots of issues and glitches in the hard raid. First off if you search on the Internet for crota movement and ogre timer it will help with some issues but others it won't. The things that ruin a good run on hard is knights coming through the glass before it breaks an kill you with one swipe of their sword the other is at the end before he enrages and when he enrages the tralls come from behind you on the top and kill you through the glass which is BS. The sword does disappear sometimes for no reason but mostly due to taking to long to kill the sword bearer as well as taking too long to to take crota down with dps. It took my team a total of 4 hours the first time to beat him. Learn the timer and you will be more successful at crota on hard. Once you know the timer well his movements right and left and as long as there are no glitches you will find the hard raid to be very easy to beat. And hopefully Bungie will fix these glitches I have mentioned above but I doubt they will.