problem with Boox Max 2 battery

[kiov.no1]

Hi everyone, I 'm having problem with Boox Max 2.
Is Its battery seem having problem ?

After full charged, I just make little manipulation, it decrease ~ 20%. (100 -> 80%)
After a night, it still decrease ~ 20% ( 80% -> 69%)

I try to do something, It don't decrease percentage immediately but it become unresponsive after ~ 2 minutes.
I try to charge it and turned it off, and after it seem not charging when it off ?
This is video record when I turned off already and started to turn on device.
https://www.youtube.com/watch?v=FbQdDr79PUs
Thanks very much!