Bug: ANT+ control function 5 and up

The ANT+ function setup works fine for function 1, 2, 3 and 4. But function 5, 6, 7 and 8 don't work. The settings are not saved in the sensor details. The edge does respond to the buttons, but you can't save the action in the edge. The edge defaults to starting and stopping an activity.

I have an SRAM AXS setup with 2 sets of AXS MultiClics and 1 set of wireless blips. One set is for additional shifting, the rest is for ANT+ control. To make use of all the buttons and combination actions function 5 and 6 are also needed.

Is this a bug, or just a limitation?