RF brake locked up. Why?

RichB said
It’s a silicone brake fluid. The main advantage is that it won’t damage your paint. The spray I had wiped right off. However, it may have leaked out easier under heat and pressure. Also, it makes for a softer brake pedal. I may go back to DOT 3.

Note in the photo that the cable is disconnected from the brake adjuster. I guess that prevented the brakes from releasing.