Writer document does not save when using a new template

I’m using collabora online cp-6.4.10-5. I’ve created a new template (.ott) using custom fonts with Libreoffice locally and I’ve uploaded via NextCloud to be used as a system wide template. I’ve also made sure to install the custom fonts in the server. When I create a new file using the NextCloud interface and select the template I can edit the document normally but it does not automatically save. It also does not save when I click the save button. I can however save as another document and then it behaves as it should. Any ideas?

This is an open issue also discussed in the nextcloud richdocuments github documents created from templates are broken and cannot be saved · Issue #1563 · nextcloud/richdocuments · GitHub with no solution yet. During document creation the file name is not correctly set in the .xml structure of the created file; I can’t see whether this is an error in richdocuments, in lool or in core.