I have seen this on several occations when the bot doesn't use its hero power when minions on board.

I don't know where to find the log or what time it was today when I saw it.

Board:
opponent: 1/1 - 2/1
Me: none

Mana: 2

I am shaman, with totem hero power.
Using default rules, not silverfish.

I don't remember my cards in hand but I remember it couldn't cast anything and the bot just ended the turn.
Instead it should had used hero power anyway. Saves life if oponent attack minion instead of not using hero power which is waste actually.

I have seen this behavior before when opponent has a few minions on turn 2 and bot just skips turn even though it could use hero power (better than doing nothing).

happened again just now again (00:38).
vs. paladin.
I had the taunt totem, oponent 1/1
2 mana

my shaman didn't use any mana and just end turn without using hero power.