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 temperatureEngine setting function (engine power control)
This function customises engine power and output.
To access the function it is necessary to view the "setting" menu page 48, using
button (1, fig. 14) ?"
"or (2, fig. 14) ?" "select the "riding mode"function
and press the
reset button (12, fig. 12) T ...
Electric system
Basic electric items are:
headlight:
low beam bulb type: 1xh7 blue vision (12v-55w);
high beam bulb type: 1xh1 (12v-55w);
parking light: led (12v-2.4W).
Electrical controls on handlebars.
Turn indicators:
front: led (13.5V-2.9W).
Horn.
Brake light switches.
Sealed battery, 12v-10 ...
Symbols
Ducati motor holding s.P.A. Advises you to read this manual
carefully in order to become familiar with your motorcycle. If
in doubt, please contact a ducati dealer or authorised
service centre. The information contained herein will prove
useful on your trips - and ducati motor holding s.P.A. Wis ...