The activation of this (amber yellow) "warning" indicates that the hands free system has detected that the battery that permits the active key (1, fig. 62) To communicate and turn the vehicle on is almost discharged.
Note
In this case, ducati recommends replacing the battery as soon as possible as described in the paragraph "replacing the active key battery" (page 88).

Hands free key (hf) not recognised
High engine coolant temperatureThe hands free module
Introduction
The hands free module incorporates the control unit communicating with the
other nodes on the motorcycle, the on/off
button, the microswitches detecting full lock steering angle (for enabling
steering lock engagement) and the steering lock.
The module is sealed and its individu ...
Keys (fig. 62)
The owner receives a set of keys comprising:
1 Active key (1, fig. 62)
1 Passive key (2, fig. 62)
It contains the code used by the "hands free" system for the
key-on, in different modes.
The active key (1, fig. 63) Is the one that is normally used:
press button (a, fig. 63) To ...
Explanation of the function of the ride-by-wire system
Mechanism
Via metal cables, the throttle grip operates a roller mounted on one end of a
spindle located near the horizontal cylinder
throttle valve spindle.
The aps sensor, which measures the position of the throttle grip itself, is
mounted on the opposite end of this spindle.
A mechanic ...