@Robb Brock Thanks for your patience on this.
I have looked at the backend logs and see that your APIM instance is Basic v2 SKU tier, and you are trying to move the instance across resource groups.
Upon investigating further and I checked with internal team on this. Team has confirmed this is a known issue and they are actively working on a fix. unfortunately, we don't have any ETA at this moment and will update here once we have any updates on this.
The only workaround available for this issue is for customer to create a new APIM service in the desired subscription, move the configuration from the old service and delete the original service.
Hope this helps, let me know if you have any further questions on this.
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