Excuse me I had meant to point you to this Version 11 to 12 data schema - AttributeError: ‘Subscription’ object has no attribute ‘naming_series’
From the traceback my guess is the autoname or naming_series spec is not set?
Maybe check in the Naming Auto Name here
https://localhost/desk#Form/DocType/Subscription
“Do we have any options beyond importing this on another fresh install?”
I am not sure whether a fresh install will reset this since it’s a data problem…
This will inform you Naming Series