XPS 13 - Battery issues after shutdown

Hello Everyone, 

I have a Dell XPS 13 9370, it's a great notebook but recently (maybe after some updates/bios upgrade) it starting showing the following issues regarding the battery, i'll try to explain my scenario as accurate as possible:

(I normally use it with a docking station so it's always charging during office hours)

1- I use it charging, and if I unplug it to go somewhere, my battery starts to behave normally, it takes almost 2,5 hours for depletion, i've tested and it does take a few hours to go down.

2- I use it charging, turn it off and take it home. When turned on (after a few hours, next day or even immediately) it shows 90 something percent battery level for a few minutes then go to critical 5%. if I turn off/on, reboot the BIOS alert will pop up about the battery.

I know it's an old model, and might even justify a new battery but it annoys me that it does hold the charge when unplugged while the laptop is on, so something happens when turned off that either drains the battery or maybe it has something to do with the several drivers/firmware updates in the previous months, as company policy we must have it as updated as possible.

I've tried a few of the answers online but no one had the first scenario described. If anyone has any suggestion or a fix it would be awsome, thanks.