Recurring nightmare bug?

I’m not sure how I got this bug to happen but, I was playing battlegrounds I had recurring nightmare, a baron, and the rest of my cards were all undead with reborn on them. Whenever recurring nightmare died and transfered to the other undeads, it would, for no reason at all, just randomly kill one of my cards, sometimes not even the one the recurring nightmare went into seeing as one of the rounds it killed my baron

So you mean that your recurring nightmare dies, it goes on another undead, and suddenly another of your minions dies for no apparent reason ?

How do you know the deaths were caused by Recurring Nightmare?