Can't find ColorStateList from drawable resource ID only on Android Nougat

I found where the problem was and how to fix it. Here's the solution, I'll keep it simple.

This line was causing the problem:

<item name="android:colorBackground">@drawable/background_splash_gradient</item>

Turns out you can't set drawable as a colorBackground in XML, so it works after removing this line.

The reason this only crashed on Nougat is because this was possible in earlier versions.