Goad doesn't work correctly

Playing against 2 AIs, I got "Marisi, Breaker of the Coil" on my battlefield (playing Commander).
In combat phase, I hit both opponents with a creature, and all their creatures supposedly got goaded.
Hovering the mouse over their creatures, I can see the "Must attack (Marisi, Breaker of the Coil)".
However, I saw 2 distinct behaviours, both wrong:
- One opponent did in fact attack with all their creatures, but attacked the other AI's planeswalker. Goaded creatures should attack an opponent of mine if possible, only resorting to attacking a PW or me if they can't. Check the screenshot for this one.
- The other opponent attacked with just one creature. The others remained there, untapped, even though they should have attacked because of the goading.
Played a few more turns, and goading just seems to be wrong, working some times, and being ignored or done wrong some other times.
Playing Marisi in a Commander game should be able to reproduce this easily, as the whole deck mechanic revolves around goading opponents' creatures every turn.