Modern Vespa

Hello,
I am new to Vespa world and looking to find advace on this forum before taking my Elettrica to the delaer.
My Vespa Elettrica does not charge if battery above 20%
Does someone know if that was made purposely to preserve battery life or something is wrong with my Vespa.
After I bought Elettrica it was sitting in my garage for over year.
It took long to charge it first time. Could it be a reason for battery not be able to charge if it's above 20%?
Please advice.

There tends to be a lot of problems if the battery under the floor has gone bad. This is a normal lead battery and is accessed with 4 torx screws.

The elettrica must be run in ready mode every few weeks to charge the lead battery or it goes bad.

I imagine this battery would need changing if it's been sat for a whole year.