Check in the macro.cnc that there is no homing command for the slave axis.
In the example below, standard homing of X, Y, Z and A is performed:
<...>
;Homing per axis
Sub home_x
home x
Endsub
Sub home_y
home y
Endsub
Sub home_z
home z
Endsub
Sub home_a
home a
Endsub
<...>
Lets assume you have configured the A axis to be slave of the X axis. Then the following changes are necessary:
<...>
;Homing per axis
Sub home_x
homeTandem X
Endsub
Sub home_y
homeTandem Y
Endsub
Sub home_z
home z
Endsub
Sub home_a
Endsub
<...>
Note that the home_a subroutine now is empty, omitting to remove the home_a function will disconnected the master-slave connection, as a result the A axis will not move together with the X axis.