Bug 433712

SUMMARY
Volume control via keyboard keys are increasing and decreasing volume at wrong amount of steps. In plasma-pa I set the volume increase and decrease steps to 1% at a time; Sometimes it changes by 1% correctly, but other times it changes by 5%.
Another strange behaviour: if I've been increasing volume, and I press Volume Down the first time, it will actually increase the volume by 5%. The second time I press Volume Down, it will then decrease the volume by 5%. The third time I press Volume Down, will then correctly decrease the volume by 1%.

It seems there is a conflict with another program, but I don't have any other volume control program or pulseaudio manager, I also looked in the hotkey list in system settings, and I didn't find any key conflicts.

STEPS TO REPRODUCE
1. Pressing volume up sometimes increases by 1%, and sometimes increases by 5%
2. Pressing volume down after volume up increases volume by 5%
3. Pressing volume down a second time decreases volume by 5%
4. Pressing volume down a third time decreases volume by 1%

This behaviour is inconsistent, and it happens in different ways depending on the order of keystrokes.

OBSERVED RESULT
Volume percentage change not consistent with the set amount

EXPECTED RESULT
Pressing volume up should increase 1% of volume, pressing volume down should decrease 1% of volume

SOFTWARE/OS VERSIONS 
Linux: 5.10.16-arch1-1
KDE Plasma Version: 5.21.0-2
KDE Frameworks Version: 5.79.0-1
Qt Version: 5.15.2

ADDITIONAL INFORMATION