[Bug] - Too many hub sites if you don't unregister them before deleting

[Tycho Bizot]

I just ran into this issue on a test tenant when testing/developing a PowerShell script to deploy a new intranet based on hub sites. 

If you create sites, register them as a hub site and then delete the sites again skipping the recycle bin without unregistering them as a hub site first you'll find out that at some point you can't create new hub sites anymore and will receive the error "too many hubsites". 

Get-SPOHubSite returns all the hub sites previously created, but since the sites don't exist anymore there is no way to unregister them.

[#2]

Tycho, just to highlight that above 50 is currently too many hub sites. I know this is not the cause of your problem but the error will be identical.

[#3 · Accepted solution]

It's a known issue and will be fixed before release. Ran into the same one. See https://github.com/SharePoint/sp-dev-docs/issues/1621