Custom class button cannot change font color

In design mode:
I am creating a new button, change the label text, create a custom class. Changing background color works. Changing the font color on normal does not apply. Stays white.

In preview mode is shows like it should with new colors on the fonts.
Perhaps this is a bug?

As I am testing with different approaches, it looks like if I create the button and then create the custom class before doing anything with the button it is working, but if I changes the label text before creating the custom class it seems not to work. I guess this looks like a bug.

I first used Blocs 3.4.5 then downgraded to 3.4.4 but no difference. Now upgraded to 3.4.5 again.