Battery not charging to 100% between 2am and 5am

Apologies if this has been asked before, I have just joined the forum. I have also looked through past posts and can't find any similar question.

My issue is, that since my battery was replaced, I have not been able to charge overnight to the full 100% battery level, it mostly charges to around 80% from 4% start. Looking at my battery charge rate between the hours of two and five it is only in the last hour or so that the battery pulls the 3.6 kWh it should, up until then it will only pull around 2.6 kWh. Attached is the graph which has occurred a number of times. There was some suggestion this was to do with battery temperature. Is 20° a magic number that means the battery will charge at the full 3.6 kWh?
Any help would be appreciated.
thanks

Joe E Is 20° a magic number that means the battery will charge at the full 3.6 kWh?

Pretty much.

20 degrees is a 'magic number' now. But it didn't used to be.

Up until around may, I had battery firmware 3012 installed and was only getting a slightly reduced charge rate at 'low' temperatures. Indeed, looking back at the charge rate graphs (I have home assistant so can view detailed history), on one of the coldest days of the year (in January) when ambient outside temp was minus 4, I was getting 3.4kW charge rate immediately and having no issues charging my Gen2 9.5 in the 3 hour slot.

Since updating to battery firmware 3017, and now temperatures are reducing (but not what I would call cold), I'm seeing 2,7 kW rates until the cell temps tip over 20 degrees.

It would appear this is an intentional crippling of our batteries that GE are remaining very quiet about.