Remove Site Collection from Site Subscription

Hello,

We are migrating in site collections from a multi-tenant environment to a non-MT web application. My understanding was that if you did a Backup-SPSite and then a Restore-SPSite it would allow you to restore a site collection that had previously been in a site subscription to an environment without a site subscription.

I did this for a handful of site collections and it worked fine. I could look up the .SiteSubscription property from Get-SPSite and it would show nothing. As a test, I could even assign a new site subscription with Set-SPSite and it would allow that to occur, even though normally if you try to change a site subscription it won't allow you to do that.

Here is the oddity. I had a number of these site collections that I had restored. They all showed no site subscription in PowerShell after restore. However, I had to do database maintenance the other evening so I dismounted the content database these site collections were in and then mounted it back. After mounting it back, the old site subscription is showing. I played around with it and it won't let me assign a new site subscription, even though it would have let me prior to the database dismount/mount.

I have replicated this behavior with other site collections in other web applications. I can reproduce the behavior each time. Dismounting and mounting a database back will take and site collections that were previously in a site subscription and reapply the old site subscription GUID.

Has anyone else run across this? Is there a better solution to permanently strip a site subscription rather than the Backup-SPSite which seems to just be temporary?

Thanks,
Joseph Irvine