Clamshell mode makes battery swell
I usually use the UltraFine 22" & 27" monitor as my primary display for the MacBook Pro 15" (2016) at home and work.
Yesterday, I found my MacBook's battery had been swollen, cause I noticed the palm rest was dangle in a flat table.
The Apple service center said it's just passed 1 month for warranty service (3 years) because the limited date was about early March. (writing today: 29/Apr. 2020)
And my service engineer said the clamshell mode would make overcharging the battery. But the clamshell mode is Apple's official function to use the external monitor, so I can't understand why there is no appropriate option (software in OS level) for protecting the MacBook from overcharging.
Is this right charging me for this fix? Is it my fault?
Thanks
MacBook