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 temperatureRemoval of the fuel tank filler cap
Remove tank covers (sect. 5 - 2, Removal of the fuel tank fairings).
Remove hoses (8) and (15) from the filler cap assembly (10).
Open the filler cap.
Unscrew the outer screws (17) securing the ring nut to the filler cap recess.
Remove the filler cap assembly (10).
...
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 ...
Checking the camshafts and supports
Check the cam contact surfaces for scratches, grooves, steps and waving.
Worn cams are frequently the cause of poor timing, which leads to loss of engine
power.
Place the camshaft between two centres and check the run-out on the areas
indicated using two dial gauges.
Service limit: 0.1 ...