I am cautiously labelling this a bug.
LM Mk1
SLB firmware 5.05b
gSender 1.4.10
I set two keyboard shortcuts for rotating the A axis. I tried several shift+ and alt+ combinations. I have had the same combinations in place for X, Y and Z axis for a long time. No combination for the A would work. gSender accepts the shortcuts, shows them as active, but the shortcuts do not work.