Comment 3 for bug 522599

I was still being idiotic. The correct fix, as pointed out by edwin-grubbs is:
            if bugtask.conjoined_master is not None:
                Store.of(bugtask).remove(bugtask.conjoined_master)

And the data was fixed by Edwin by using affects projects link to add a gdp bugtask back to the bug. The lesson learned is that conjoined bugs are very loosely coupled. The relationship is inferred from state.