It is also random for me. The card is working as intended/normally in many other games I played but today it just bugged out as my opponent played it. I also found some posts on the blizzard forums that they are aware of the bug, let's hope it gets fixed soon.
I am not gonna play anymore due to the sheer amount of priests in wild and losing to this gamebreaker feels very upsetting :(
I've seen this bug happening in a few places - including on streams occasionally.
I've also seen someone suggesting that triggering the download function in the game on mobile helps solve it, but I can't confirm that as there was no evidence for the fix that I could see. Best I can suggest is wait for Blizzard to make a hotfix patch.
I actually did have this happen about two weeks ago, I Togwaggled, they Psychic Screamed, and I kept drawing empty slots in my hand. I figured it was from the weird deck interaction of Togwaggle but looks like its a thing.