Brand Passive, Liandrys and Elder Drake

I'm not sure if this is a bug, but I was in game and the enemy team had killed the elder drake, A friendly maokai had acquired 3 stacks of brand passive and walked into me, unknowingly killing me from 600 hp (after the 3 stack blaze detonation) (with a max hp of 2200) with the combination of liandrys, brand passive, and the true damage from the elder drake buff. I counted at least 6 procs of 75 true damage. The brand did not even have a sorc pot. This seems a little rediculous to give more than 1 proc of the true damage from elder buff from one DoT passive. So what I'm asking is, is this intended? Information on the elder drake buff is pretty hard to come by.