How can the battery get discharged while Ampere is showing that it is charging? How can the battery get discharged while Ampere is showing that it is charging?
Example:
At 1:06 PM, the battery indicates 2%.

At 1:08 PM, the battery indicates 1%, even though Ampere says that the min mA was strictly positive (40 mA).

How is that possible?
I use Android 10 on Samsung Galaxy S9.
As said in the comments, the issue is that Ampere doesn't take into account the battery consumption when showing the charging current.
Example:
AccuBattery, which takes into account the battery consumption when showing the charging current:

Ampere: