I have a question and it drives me nuts

Having a project with a master frame and some content frames.
Breakpoints are set at any page with: Default (1280), 1024, 768, 375 & 320. Set "Active BP when browser is larger than device width" (default setting).
Regarding BP, everything is working fine on various devices except when using a big screen:
A standard button, embedded in a layer, renders perfectly in all BP, but not in 1280+
The button is set to green, white font, RWD and has different sizes in BP´s, but in 1280+ it renders as an empty white box. In the editor it looks fine in all BP.
Did a lot of research, but have not found a way...
How can I achive that the button renders as wanted?
Thanks
Note: as far I remember, It rendered correctly in WWB14, but cant proof as I migrated early and don´t use the big screen a lot.