Bug 447225

SUMMARY
*** 
I have used the editor kate for about 20 years now. After a recent update, I experience a strange behaviour. When I want to input quotation marks, the cursor "jumps" one character to the right, putting the quotation mark *after* the character, where it should be before

Suppose I want to add quotation marks around "hello" as shown below. At first, I get ¨, which indicates that a composing character has been input, which is waiting for another keypress to decide whether it should become ä, ö, ü or, in this case ". This character ¨ appears where it should appear. As soon as I press <SPACE>, however, it jumps one character to the right. 

`s = hello`
`s = ¨hello`
`s = h"ello`

The same is true for the ' combining character. If I want to correct "Cdiz" to "Cádiz", I get the following
`s = hello`
`s = ´hello`
`s = h'ello`
 
The issue does not occur with ^ or `.

The issue occurs with other Qt-programs (kile, open-scad). It does not occur with non-Qt-programs.

Input via other keyboard layouts (german) is fine.
***


STEPS TO REPRODUCE
1. Set keyboard to "US alt. intl."
2. Input 123456
3. Position cursor between 3 and 4
4. Type "
5. Type " again. 


OBSERVED RESULT
1234"56

EXPECTED RESULT
123"456

SOFTWARE/OS VERSIONS
Windows: -
macOS: -
Linux/KDE Plasma:  
(available in About System)
KDE Plasma Version: 5.22.5
KDE Frameworks Version:   5.86.0
Qt Version:  5.15.2 

ADDITIONAL INFORMATION

 xcb windowing system