Is the content type hub broken?
I'm based in the UK and my current customer relies on the content type hub to provide their information management policies across SharePoint. It's not a new thing and the use of content type hub publishing has been with us since 2010. I've even worked with a colleague a few years ago to create an automated publisher for SharePoint Online, which authenticated against the SPO chub page and used scraping to press that 'Publish' button!
Many customers rely on it, so why did Microsoft break it?
As content types take time to publish to new site collections during creation I've often had to code a 'poller' to check if the content types are available, once that SharePoint timer job has done its thing the next phase of provisioning can continue, such as applying these to inbuilt document libraries to enforce an information management policy. This is very similar to my current customers provisioning tool.
The only thing - these content types have stopped appearing and the provisioning tool sits in an endless loop eventually timing out.
The content types aren't overly complicated, a few managed metadata fields and minimal inheritance (maybe one deep) - everything appears ok. We reach out to Microsoft and within hours have a reply that we're not the only customer facing the issue. They roll a fix out to the sites we've provisioned which didn't have the content types applied, I hope that's not a strategic fix! "Ok Microsoft we've built 2 sites, can you do your thing please".
We suspect they're just pushing out the content types configured in the chub directly on the site, which we could easily do but are reluctant as we don't want to break something in the future.
I'd be interested to hear if you're facing a similar issue, get in touch on LinkedIn!
On a side note - I checked it out on my own Tenant, everything's working as expected