Bug 452071

STEPS TO REPRODUCE
1. Create a cal dav server (e.g. https://sabre.io/baikal/)
2. Import (not via akondai) a ton of appointments (let's say 100) spread out (over several months)
3. Add the resource to akondai and let it synchronize all appointments (without a time limit)
4. Not all appointments can be seen in akondai (e.g. in korganizer or in the dev console)

Another way to reproduce is:
1. have 2 cal dav resource configured
2. move an appointment from 1 cal dav resource to another
3. oberserve that it does not get synchronized to the cal dav server


SOFTWARE/OS VERSIONS
Operating System: KDE neon Testing Edition
KDE Plasma Version: 5.24.3
KDE Frameworks Version: 5.93.0
Qt Version: 5.15.3
Kernel Version: 5.17-051700-generic (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 5500U with Radeon Graphics
Memory: 17.5 GiB of RAM
Graphics Processor: AMD RENOIR

ADDITIONAL INFORMATION
This is a production device and it used fully normal data. I am using it on 2 devices (both on newest version) and the appointments don't get synchronized correctly.

(With correctly I mean: Some events get synchronized and some will. If you take a look into the dev console, you can see the appointment ids. they start (in my case) at 1, go up to 15, then some gaps and then suddently from 104 to 423. there may be some missing, because they got delteted, but not 300. On my android device with davx5 everything works fine.)