It’s been quite a while since I’ve gotten any bonus heroes. Statistically, that might be totally reasonable. However, every once in a while, I’ll pull a cover and get that starburst animation that announces the bonus cover. “Great! I wonder what it will be,” I think. Then, alas, no second cover.
Figured I’d check in and see if I’m the only one who has seen this. I’m on iOS, as a data point.