Spires of Orazca not debuffing Tokens

[span_argoman]

I played a match with Spires of Orazca out and the opponent Garruk had his board clear. On his turn he then proceeded to trigger his first ability for a 4/4 Snake token.

At this point, Spires of Orazca should have reduced its power to 0 like when creatures are summoned. However, nothing happened and next turn the Snake token attacked normally.

[wereotter]

It also isn’t working with creatures that buff themselves on entry. For example you can have it out, and your opponent can bring out Olivia, and she’ll still hit you for 3