Neptulon bugged with Hysteria

Imgur link below with a clip, but the replay starts a little too late. Directly prior to the replay I played Hysteria on my opponent’s Neptulon the Tide Hunter. Upon destroying the first of his arms, he bugged out while attacking his other arm until the interaction stopped completely, although the Hysteria did not play out and resulted in my opponent having lethal damage on board the next turn. Would love some insight as to why this happened, as I’m sure this is a result of Neptulon’s card text that causes his arms to attack for him but I do not know if this is an intended mechanic.

Please note due to the inability to submit links in these posts, I had to place a space between the C and the O of the imgur link. Remove it if you’d like to see the replay.
Imgur link: imgur.c om/a/XiNaYaA

Neptulon attacks his one remaining arm. Due to card texts, this causes his arm to attack itself, but a card cannot attack itself in Hearthstone. So that attack fails.

What surprises me is that after that same attack consistently is done over and over. There’s also a 9/9 on board so why is that never chosen as the random target?

That the repeats eventually end makes sense. Hearthstone has hidden maximums for (almost) all effects that in theory could sometimes go on endless repeat; once the maximum is exceeded the effect is stopped.

A lot about this interaction confuses me- namely the repeated attacking of the hand, which is already at negative health and should therefore not be targetable by a hysteria minion if i understand it correctly.

Got the same error yesterday. i Lost the Game for the fault of this bug.