USB pendant stops working after using macros

Hi all

I have a dragon rise USB board (pendant) attached to one of my machines. When I first home the machine all of the buttons work as expected (IE I can jog the machine around)

After I press one of the macro buttons on the screen ( Switched Home or Work Zero) the USB pendant stops working.
I'm guessing that the macros are not exiting properly but I can find no errors.
I am running debian 3.10 with LinuxCNC 2.9.4

I'm hoping someone can give me some pointers on this.
Thanks
Alex