SUMMARY
Double pressing on "+" triggers a "*2" operation, which is incorrectly rendered on the right-hand side panel.


STEPS TO REPRODUCE
Let's calculate 2+2+3...
1. Press "2", "+", "2", "+", "3", Enter
2. Now let's use the "double plus" shortcut: press "2", "+", "+", "3", Enter

OBSERVED RESULT
The first calculation is correctly rendered as "2 + 2 + 3 = 7"
The second calculation is incorrectly rendered as "2 + 2 + 3 = 5"

EXPECTED RESULT
Two possibilities:
- Either the double press on "+" is handled as a "*2" shortcut and the second calculation should then be rendered as "2 + 2 + 3 = 7", or
- (my preference) the second press on "+" is just ignored, which would result in the second calculation being rendered as "2 + 3 = 5"

I prefer the second option, which is just not having a "double plus" shortcut, because when entering long series of addition terms, I sometimes lose track of whether I have already pressed "+" after a term, and I would prefer being able to re-press "+" without risking to have a term counted twice

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kali Linux 2023.1 (based on Debian testing)
(available in About System)
KDE Plasma Version: 5.27.2
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8