Exponential "Brightness step count" does not work with panel scrolling

System

Dell Latitude 3380 (i5-7200U / 8GB RAM)
MX Linux 21.3 (Debian 11.x + XFCE 4.18)
Xfce Power Manager 4.18.0

Context

• Set "Brightness step count" to 20 and turn on "Exponential" (All fine):

• Change the brightness with brightness buttons (It works):

• Change the brightness scrolling in the plugin's popover (It works):

• Change the brightness by scrolling directly on the panel's icon. — I recorded the bug with my phone because there's no indicator that the brightness is changing. — Due to an Automatic White Balance, only screen off/screen on is noticeable.

Documentational video

Replication

I found/noticed that doing the "Context" part in order could make the Exponential Brightness work, however, with a fresh boot it simply does not work.