SUMMARY
When trying to record a sequence of keys as a shortcut, it is not operational, nor it is stored properly and the conflicts are checked by the first combination in the sequence.

Example: I'm trying to record sequence Meta+Left,Meta+Down (Meta+Left followed by Meta+Down) to 'Quick pack window bottom-left' and Meta+Left,Meta+Up to 'Quick pack window bottom-left'. However, this fails with an error "The shortcut 'Meta+Left' conflicts..."


STEPS TO REPRODUCE
1. Assign the sequence Meta+Left,Meta+Down to 'Quick pack window bottom-left'
2. (observe that the shortcut is displayed correctly within the widget, but not the table)
3. (observe that the recorded shortcut does not work)
4. Assign the sequence Meta+Left,Meta+Up to 'Quick pack window top-left'
5. (observe the pop-up dialog stating about the shortcut conflict)

OBSERVED RESULT
The shoctcuts are not recorded properly, not stored properly, are non-functional, results in a conflict where there shouldn't be one.

EXPECTED RESULT
1. The shortcut sequence works
2. It is shown correctly in the table
3. No conflict arises between sequences: "Meta+Left,Meta+Down" and "Meta+Left,Meta+Up"

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Ubuntu 19.10, Version 19.12.3
(available in About System)
KDE Plasma Version: 5.18.3
KDE Frameworks Version: 5.67.0
Qt Version: 5.12.4 (built against 5.12.4)

ADDITIONAL INFORMATION