HUB Association and changing site address

Hi all,

due to a change of business units in our organization, we needed to change site addresses of some sites (around 50) because our URLs relay on a naming convention including a short for business unit.

One of these Sites was a HUB-Site and three of them were associated to that HUB.

We removed the HUB registration from the HUB-Site by UI in Admin-Center which removed the association to the three other sites also.

If I then tried to change the Site-URL of the previous mentioned HUB-Site, UI and Console had errors. - OK, I know there is a delay sometime, so i waited until the next day and did a retry.

Now, changing the site address was working.

Then I tried to change the site address of the three other sites, which were previously associated to the HUB.

The UI and even the console are telling me, that I cannot change the site address, because this site is a HUB site and I should deregistster this site as a HUB-Site:

This happens to all three sites if I try to change the site address.

NONE of these sites have ever been a HUB-Site!

The console has two errors regarding this action.

First means "no renaming order for the site":

Second is "This site is already a Hubsite":

If I view the three site in admin center they are shown without any association:

If i Open up the Details-Panel, I can see 'None' for Hub Association: 

If I then click Edit, the DropDown is empty, but here should "None"

Even if I try to change the site address by PS with 

Start-SPOSiteRename and parameter -ValidationOnly, I get the same error message, that this site is a Hubsite, which is of course not true:

Does anybody run into the same issue and may have a solution?

Thx, Ronny