LibreOffice cannot write to WebDAV or sftp

When opening a file on WebDAV in LibreOffice it is correctly opened through kio-fuse. Trying to save it after editing gives the following error message:

Error saving the document Test:
Unknown input/output error while accessing
/run/user/1000/kio-fuse-CVZNIt/webdavs/medhefgo@webdav.smartdrive.web.de:443/Test.odt.

Also, when you try to create a new document and save it, the kde file browser is used, which apparently will not return a kio-fuse based filename, but rather returns the WebDAV URL directly, resulting in a user/password prompt within LibreOffice.

When trying to open a file on SFTP, I get the following error message:

The lock file could not be created for exclusive access by LibreOffice,
due to missing permission to create a lock file on that file location or lack of free disk space.

Trying to save a file directly through kio-fuse by browsing to the location under /run will result in this error message:

Error saving the document Untitled 1:
Object not accessible.
The object cannot be accessed
due to insufficient user rights.