So I just fought another 4x Kerberos deck and I was able to get some screenshot. So here’s the sequences.
I wiped all Kerberos and 3 of them trigger Gate Guardian and 4 Wargs summoned. Nothing wrong so far.
I wiped 4x summoned Wargs and somehow Gate Guardian still triggered even though there was no Kerberos on the enemy side. I also noticed my AoE only hit 3 of them, last warg didn’t get hit by my AoE. So I guessed that’s where the “Ghost” Kerberos.
Then TADAAA, I was right. The Ghost Kerberos somehow appeared in the last spot.
Then I casted my Rowanne, but it only hit the first Warg for 62 damage (my Rowanne could deal 117 damage split). Warg died and it spawned another warg FROM GATE GUARDIAN provided by Ghost Kerberos.
After approximately 29 minutes, I finally able to “finish” the battle while 3 ghost warg and kerberos still there. And guess what? Yes I was stuck in the spinning wheel.
As I said before, I doubt lowering the chance would fix this bugged. I hope I provided enough feedback so devs would fix it on the right spot next time they do that.