My MacBook Air's battery sometimes discharges overnight. Not always, perhaps just 60% of the time. It is always on sleep (I just close the lid) and it is usually for 8-9 hours. I unplug it, close the lid and head to bed. In the morning, it is at either 87% (most times) or 98% (some times) or 100% (rarely). I could not discern any pattern.
2017 13" MacBook Air (Purchased early 2019)
macOS Mojave 10.14
What I tried so far:
The issue is that I don't really know how to debug this.