[SOS] Herald of Amity ETB doesn't take effect

[rpherbig]

Describe the bug
I played Herald of Amity. The ETB went on the stack, but when it resolved nothing happened. I was not shown the top 8 cards, I was not offered an Aura to play.

To Reproduce
Steps to reproduce the behavior:

1. Play Herald of Amity

Expected behavior
I expected to have been shown the top 8 cards of my library, even if none were Auras.

Screenshots

Desktop (please complete the following information):

• OS: Windows

Additional context
n/a

[rpherbig]

Today I cast HOA and it behaved differently: the popup appeared showing 8 cards (and only Auras were highlighted), as expected. However, when I clicked on one, it did not cast. It's not in my graveyard, hand, or battlefield.