P Not sure I understand exactly the sequence but it sounds as if it is doing a recalibration, part of which is a full discharge, before they fully recharge, however, I could be wrong. However as you've updated the F/W that is a prime candidate I guess.
I have an AC3 and the batteries are at the latest level and mine shows:
Inverter F/W D0.535-A0.536 - Battery F/W 3015
If you look at BELL ICON - Notifications at the top of the left hand menu in the Portal. Have you got any notifications in there?
If you look at 'My Inverter'> 'Settings
Make sure ECO is Enabled
Timed Charge - Set to your normal times if any
Timed Discharge - Disabled
Timed Export - Disabled
Battery Options - Reserve 4% or so, if close leave alone, Charge & Discharge both Maximum
Look at the 'Power Graph' does it look as it is really discharging and is the percentage dropping?
When I did my upgrade to the latest firmware it hung on recharging the batteries but a:
'My Inverter' > 'Settings' > 'Reset to Defaults' > SUBMIT (Make sure you get a positive acknowledgement, if not try again - do not rush)
You could perhaps at a push try the support line: 01377 254 874 in case there is any cover over the Christmas break,