The rear brake on my 2010 Kona Major Jake has similar ‘open’ stops. On the Kona, it’s for a full outer and there was -originally- some kind of grommet supplied that retains it in the stop (I don’t have these, long gone when I acquired the frame).
I have temporarily solved the issue with a frame bag that also helps to retain the cable - because the Kona is used as a transporter, it’s not a problem.
The rear brake on my 2010 Kona Major Jake has similar ‘open’ stops. On the Kona, it’s for a full outer and there was -originally- some kind of grommet supplied that retains it in the stop (I don’t have these, long gone when I acquired the frame).
I have temporarily solved the issue with a frame bag that also helps to retain the cable - because the Kona is used as a transporter, it’s not a problem.