I’m creating the main UI for my project and i need to change the button colours in normal, hovered and pressed states.
I have a black coloured images as base texture, and i want to tint it to other colours, but it does not work:
Why?
You will need to change the base color on your arrow to white, then it will work. Can’t tell you exactly why this is happening, but it does work for me with white arrow, doesn’t with black one.
Not sure it’s a bug, probably just something we/I have no idea about. 
You are right man, should we report this as a bug?