Hi Jose,

12,9V after 20hours of charging does not warranty that battery capacity is 110Ah if the batteries are rated to be 110Ah. Your measurement after you disconnected charger are showing that battery capacity much lower than rated 110Ah. This is why you have 22V in the morning.
Maybe you should record charging current as you are charging now. Maybe one measurement every 15 minutes. The voltage and charging current. And when you disconnect charger measure the same. Keep your loads at minimum. Fridge, freezer..
Talk to Mastervolt technician,  he need to know that something went wrong with your batteries to prevent this happening again. 

--
Slavko
SM 2000
#279 Bonne Anse in Croatia