Icebreaker is not dropping past the first clear on each character. I have done Vespers Host 35+ times this week with people who also do not have Icebreaker and it has not dropped. That's not all, I have been speaking to people who have been farming this week and no one has seen Icebreaker drop past the first clear on each character. The drop rate is bugged as it is extremely statistically unlikely to have over 100+ clears and not a single player getting Icebreaker. The chances of this many clears and not seeing any member of my fireteam getting a drop is less than a 0.1% chance with the assumed drop chance of 5% (This doesn't included any drop chance increasing triumphs which we all had).