I recieved the latest firmware update a few weeks ago for my Esseesse9+ and started seeing similar behavior (from: FW:EN.A.002616.037 BDY:5.0.1 DSB:218 to FW:EN.A.002616.039 BDY:6.0.1 DSB:232)
Originally I received a "Key Not in Range" on my ride back from the dealer. At first I though I left my key back at the dealer, but there it was in my front pocket. Over the next week or so, I received the error a few more times. My first thought was the battery - so I checked it (nominal) and verified the key range (nominal 1.5m).
I have not had any "Key Not in Range" lately, but I do have starting issues. Essentially, to start the bike I press & hold the E-Keyless button for 3 seconds - the red immobilizer light flashes twice. I then press & hold the E-Keyless button again for 3 seconds - the system boots normally. This happens about 90% of the time.
I needed the firmware because it helped resolved a couple of issues, one being an even more annoying starting issue ...
The behavior and my work around was as follows:
turn bike on: press ignition button for 3 sec
boot sound & boot screen show on display
normal dashboard screen flashes, then it goes black
turn bike off: press ignition button until red immobilizer light flashes
turn bike on: press ignition button for 3 sec
boot sound - black screen
turn bike off: press ignition button until red immobilizer light flashes
turn bike on: press ignition button for 3 sec
boot sound - boot screen - normal screen
This behavior went away with the firmware update.
Also, last year, one day before I switched the motor off with the kill switch, I put down the kickstand (activating the motor shutoff interlock.) This caused an erroneous "fused contactor" error that I had to have fixed at the dealer. I was told this is a very rare event (Energica said it has only happened twice - lucky me), but this firmware version should prevent this from happeneing and, additionally, it provides a method for an internal cycling of the contactors (previously, it is my understanding, it had to be done with an external power source).
In any case, I needed the update.
... and this starting issue is a minor inconvenience - my other bikes are 1960's european bikes - where starting a bike is generally quite a production