No gems for defense

Why did I not get gems for this won defense with a resurection? Why?

 

because it’s a 1: 4 conversion, if he spent 3 or less, you just will not get it.

You gain 13% of the gems. So if it’s a low level hero, you could get nothing.

That is ridiculous

Even if he spent close to nothing, it should give at least +1 gem.