SUMMARY
When you try to annotate and then overwrite a file stored on a Windows network share, from a Windows PC you get an error message related to copying the partial file to the real save location. This only happens when you access the files with the "\\share\location\file" type syntax, it works if you map the share to a letter drive (marked minor because of this workaround). It also works if you save a new file, it's only overwrites that break it.


STEPS TO REPRODUCE
1. Open file on network share without mapping the share to a letter drive. E.g. "\\SHARE-PC\SHARE-NAME\test-file.pdf" 
2. Overwrite the original file with File->Save As
3. Select Yes when asked to replace the file.

OBSERVED RESULT
The file is not saved and the following error message is displayed in a popup: 

File could not be saved in 'file://SHARE-PC/SHARE-NAME/test-file.pdf'. Error: 'Could not rename partial file //SHARE-PC/SHARE-NAME/test-file.pdf.
Please check permissions.'. Try to save it to another location.

EXPECTED RESULT
The file is saved.

SOFTWARE/OS VERSIONS
Windows: 10 Pro 22H2
macOS: N/A
Linux/KDE Plasma: N/A 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 5.109.0
Qt Version: 5.109.0

ADDITIONAL INFORMATION
I got my Okular binaries from the MS store.