Teemo DOT broken

Earlier today i queued as Tryndamere, i loaded into the game late because of some server issues (no surprise), but the worst thing that happened was my ult didn't seem to be keeping me from dying, and every time i would die to Teemo. i eventually realized that for some reason Teemo's damage over time ticks were still hitting me after i hit 1 health, killing me. I made sure that it wasnt my ult running out and, sure enough, it wasn't. I would activate my ult, and within 1-2 seconds, i would die to teemo's DOT. i wouldnt have thought much about it except that it happenend multiple times through multiple matches.