Same to me but from the other side. Was vs Kiora who played a Hlaavin, it picked up relentless, I killed it 2 turns later but instead of reviving with relentless, it vanished off the board, then I kept being promoted to defend against creature that wasn't on the board and when I passed getting damaged by nothing. The Hlaavin was still there to my opponent, but I couldn't see or interact with it on the screen.
Same to me but from the other side. Was vs Kiora who played a Hlaavin, it picked up relentless, I killed it 2 turns later but instead of reviving with relentless, it vanished off the board, then I kept being promoted to defend against creature that wasn't on the board and when I passed getting damaged by nothing. The Hlaavin was still there to my opponent, but I couldn't see or interact with it on the screen.