Any sprite using the default unity sprite material in the 2D sprite renderer will appear broken when it should have transparency.
In the screenshot attached, the 2 sprites on the left are using 2 different custom sprite shaders.
The one on the right is using the default shader.
The last time I uploaded a world with sprites was on Saturday. So something went wrong with vrchat inbetween then and now.
I've also tested 2 different sdks with blank projects and the results were the same.
SDKs tested on:
VRCSDK-2019.06.19.20.14_Public
VRCSDK-2019.06.04.14.12_Public
Also this only happens to new uploads/updated worlds.
I've also linked to the world with all 3 sprites shown in the screenshot if it makes it easier to test: