Leaving combat

I understand the timer on leaving combat is 6 seconds from doing anything combat related? How come half of the streams I watch of “rank 1” druids they are restealthing no more then 3 seconds after being nuked? I watched a guy earlier get switched on, raped through kidney, travel formed, wild charged, regrowth and restealthed at the end of the regrowth. No more than 2.5 seconds are he was last hit. I literally counted. That and it seems casting healers restarts the timer for me. Did they recently change this or like wtf is going on?