Kalendar has stopped accpting new events

when i try to save an event from kalendar i now get this error

Screenshot_20230930_190415

any tips on how to trouble shoot this?

Operating System: Kubuntu 22.04
KDE Plasma Version: 5.24.7
KDE Frameworks Version: 5.98.0
Qt Version: 5.15.3
Kernel Version: 6.2.0-33-generic (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-2600 CPU @ 3.40GHz
Memory: 11.7 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 960/PCIe/SSE2

UPDATE: enabling
https://ppa.launchpadcontent.net/kubuntu-ppa/backports/ubuntu/
https://ppa.launchpadcontent.net/kubuntu-ppa/backports-extra/ubuntu/
has brought my plasma up to 5.27

Operating System: Kubuntu 22.04
KDE Plasma Version: 5.27.8
KDE Frameworks Version: 5.104.0
Qt Version: 5.15.3
Kernel Version: 6.2.0-34-generic (64-bit)
Graphics Platform: X11

the condition still persists.

when i run kalendar with the gdb tool, this is the output when i try to create a new future event which results in the above dialog box.

(gdb) run
Starting program: /usr/bin/kalendar 
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
QML debugging is enabled. Only use this in a safe environment.
[New Thread 0x7fffef37f640 (LWP 34608)]
[New Thread 0x7fffede73640 (LWP 34609)]
[New Thread 0x7fffecbff640 (LWP 34610)]
[New Thread 0x7fffe27ff640 (LWP 34611)]
[New Thread 0x7fffe1ffe640 (LWP 34614)]
[New Thread 0x7fffe0fbd640 (LWP 34615)]
[New Thread 0x7fffc9d2c640 (LWP 34622)]
[New Thread 0x7fffc952b640 (LWP 34623)]
[New Thread 0x7fffc8d2a640 (LWP 34624)]
[New Thread 0x7fffc3fff640 (LWP 34625)]
[New Thread 0x7fffc37fe640 (LWP 34626)]
[New Thread 0x7fffc2ffd640 (LWP 34627)]
Hspell: can't open /usr/share/hspell/hebrew.wgz.sizes.
kf.sonnet.clients.hspell: HSpellDict::HSpellDict: Init failed
qrc:/DatePicker.qml:33: TypeError: Cannot read property 'startDate' of null
qrc:/DatePicker.qml:33: TypeError: Cannot read property 'startDate' of null
qrc:/IncidenceEditor.qml:400:17: QML ComboBox: Binding loop detected for property "currentIndex"
qrc:/IncidenceEditor.qml:400:17: QML ComboBox: Binding loop detected for property "currentIndex"
qrc:/DatePicker.qml:33: TypeError: Cannot read property 'startDate' of null
qrc:/DatePicker.qml:33: TypeError: Cannot read property 'startDate' of null
[New Thread 0x7fffc0c2c640 (LWP 34630)]
qrc:/TimePicker.qml:151:21: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
qrc:/TimePicker.qml:151:21: QML Connections: Implicitly defined onFoo properties in Connections are deprecated. Use this syntax instead: function onFoo(<arguments>) { ... }
qrc:/TimePicker.qml:257:13: QML Rectangle: Binding loop detected for property "height"
qrc:/TimePicker.qml:257:13: QML Rectangle: Binding loop detected for property "height"
[New Thread 0x7fffa7bff640 (LWP 34631)]
qrc:/IncidenceEditor.qml:570:33: Unable to assign [undefined] to bool
[Thread 0x7fffa7bff640 (LWP 34631) exited]
"Invalid parent collection"
[New Thread 0x7fffa7bff640 (LWP 34636)]
[Thread 0x7fffc3fff640 (LWP 34625) exited]
[Thread 0x7fffc8d2a640 (LWP 34624) exited]
[Thread 0x7fffc952b640 (LWP 34623) exited]
[Thread 0x7fffc9d2c640 (LWP 34622) exited]
[Thread 0x7fffe27ff640 (LWP 34611) exited]
[Thread 0x7fffecbff640 (LWP 34610) exited]
[Thread 0x7fffe0fbd640 (LWP 34615) exited]
[Thread 0x7fffc37fe640 (LWP 34626) exited]
[Thread 0x7fffe1ffe640 (LWP 34614) exited]
[Thread 0x7fffc0c2c640 (LWP 34630) exited]
[Thread 0x7fffef37f640 (LWP 34608) exited]
[Thread 0x7fffa7bff640 (LWP 34636) exited]
[Thread 0x7fffede73640 (LWP 34609) exited]
[Thread 0x7fffc2ffd640 (LWP 34627) exited]
[Inferior 1 (process 34605) exited normally]
(gdb) bt
No stack.
(gdb)