I have a question about the T8 and the towers to which I hope someone would know the answer to. My group is currently working on the last phase of the fight and while we don't have issues with any other mechanics and feel like our tower rotation is working for us, there's one thing that occasionally wipes us and we don't understand how it works.

Sometimes when Allagan Field and Defense Reaction are supposed to explode at the same time, DR goes off a couple of seconds faster increasing AF damage significantly and basically one-shotting almost everyone in the group. The thing is, sometimes they blow up the exact same time and everything goes perfectly, then sometimes there's a difference of a couple of seconds and we wipe. I'd like to understand why this happens. I suspect it has something to do with either when we move to phase or when people activate their towers.

Our tower order is following:
1st set: Mines (2), DR2 (1), DR1 (0)
2nd set: DN (2), Mines (1), DR1 (0)

The random AF+DR happen during the first defense explosion in first set and the only defense explosion in 2nd set.