Document template in an imported content type recently broken in SharePoint Online?

I am developing a solution where I have to create around 50 sites that are identical besides their names.
Each site will contain a document library with the same custom content type that has a custom document template.

I achieve(d) this by creating a content type on the "contentTypeHub", attaching a document template to the content type, and importing that content type to all the sites in the installation script and then adding that content type to the document library.

This worked fine and as expected up until a few weeks ago (up until about week 28).

I went on vacation for 4 weeks (weeks 28-32), did some other stuff for 2 weeks, and at the start of this week (week 34) I ran some test on the installation script (which had not been changed since it last worked) and now the document template cannot be found.

The content type, along with the document template, is still being imported to the new site and the document library, but if I try to create a new file with the document template SharePoint says that the file cannot be found. Installations before week 28, with the exact same script, still works fine. I'm getting the url of the template by fetching the content type and using the attribute "DocumentTemplateUrl" ($contentType = Get-PnPContentType -Identity $contentTypeId) which returns a relative url that cannot be reached.

Has something changed about the location of the document template?