Guild Wars 2

I was playing skyhammer and I killed an ele. The ele did its mist form downstate into an open hole around the point (point c). I didn’t get a kill and its summons remained (attacking me), then I noticed the point wasn’t capping. I moved off it and the ele popped out of nowhere at low health. I don’t understand what happened, is it a bug?

Had that happening to me few days ago as well. I thought I had him and i moved on (i lost the target so i thought he died) and then a few moments later he was riding the lightning toward me, LOL