I just played a game as Dr. Mundo vs Yorick in the top lane. Long story short, I got wrecked because Yoricks mistwalkers apply grievous wounds if Yorick has a mortal reminder or executioner's calling.
I was wondering why I lost lane so hard and then I looked at Yoricks items. He had a mortal reminder (the item with the passive that causes grievous wounds) and I then I closely watched what was going on in our small exchanges. Yorick would E me, and then his mistwalkers would jump on me hit me once or twice. I'd kill all of them quickly but then I noticed the grievous wounds symbol over my head and then I realized that every time I would fight Yorick I was basically under perma grievous wounds and I was misjudging how all our previous fights went down.
My question is, why is this an interaction and should it be an interaction? Because his mistwalkers dont apply rylais slow, life steal, or other on hit effects, so why is grievous wounds special?